This equation implies two things. First buying one more unit of good x implies buying {\displaystyle {\frac {P_{x}}{P_{y}}}} less units of good y. So, {\displaystyle {\frac {P_{x}}{P_{y}}}} is the relative price of a unit of x as to the number of units given up in y. Second, if the price of x falls for a fixed {\displaystyle Y} , then its relative price falls. The usual hypothesis is that the quantity demanded of x would increase at the lower price, the law of demand. The generalization to more than two goods consists of modelling y as a composite good.

Investing in rental properties: Another form of real estate investment, rental investments (i.e. becoming a landlord) could steer you down the passive income path of steady monthly rent checks that you can use to pay off a mortgage loan on the rental property. After the mortgage is paid off, those monthly checks go right into your bank account -- potentially for years to come. 

With $200,000 a year in passive income, I would have enough income to provide for a family of up to four in San Francisco, given we bought a modest home in 2014. Now that we have a son, I'm happy to say that $200,000 indeed does seem like enough, especially if we can win the public-school lottery to avoid paying $20,000 to $50,000 a year in private-school tuition.
The theoretical generalization to more than one period is a multi-period wealth and income constraint. For example, the same person can gain more productive skills or acquire more productive income-earning assets to earn a higher income. In the multi-period case, something might also happen to the economy beyond the control of the individual to reduce (or increase) the flow of income. Changing measured income and its relation to consumption over time might be modeled accordingly, such as in the permanent income hypothesis.
I found this to be a fascinating and most helpful book. It was so motivating I'm already working on three new streams of income, and about to start a fourth. Forget net worth! Cash flow is much more important, particularly if you're retired. Only one slight criticism of the book. It's a bit dated, but those few parts make little difference to its overall value. If you're currently struggling with how you're going to survive after you retire, try Allen's approach. It will open your eyes.
If you are unfortunate enough to find yourself no longer able to physically work in your chosen position, developing a skill set that will allow for a complete career change is a must. The passive income route as a second career is a great backup allowing you to hire out what you can’t physically do. Early on in my career I found I was unable to physically tolerate exposure to tobacco smoke. At that time, smoking was allowed in all offices, restaurants, etc. I was blindsided; who ever thought? It virtually removed me from most positions I had schooling for. As luck would have it, I had purchased a duplex while working and saved a small sum. When I had to leave my career, I made a down payment on another duplex doing any maintenance I could myself. If a physical setback of another sort should happen, I can hire.

Increase in income Income per capita has been increasing steadily in almost every country.[5] Many factors contribute to people having a higher income such as education,[6] globalisation and favorable political circumstances such as economic freedom and peace. Increase in income also tends to lead to people choosing to work less hours. Developed countries (defined as countries with a "developed economy") have higher incomes as opposed to developing countries tending to have lower incomes.
I like the way you have listed the ways to earn extra income and was quite surprise that you did not make mention of network marketing, which is a way to make extra income without quitting your regular, though most people view mlm as a pyramid scheme but the real pyramid scheme is a regular 9 to 5, because you can only have one president of a company at any given time and network marketing business model to promote product that can be used is really cheap to join and can offer a substantial extra income or what do you think?
The long-term growth prospective of the Indian economy is positive due to its young population, corresponding low dependency ratio, healthy savings[38] and investment rates, and increasing integration into the global economy.[39] India topped the World Bank's growth outlook for the first time in fiscal year 2015–16, during which the economy grew 7.6%.[40] Despite previous reforms, economic growth is still significantly slowed by bureaucracy, poor infrastructure, and inflexible labor laws (especially the inability to lay off workers in a business slowdown).[41]
Multiple Streams of Income is chock full of advice. The investing advice is also great and certaintly better than what you will find say in JBQ's ridiculous book which cost many people millions in lost dollars. I saw a review here by Mr. Donoghue. My guess is that some people will try to bury that untill mindless 1 star reviews. If you can scroll back and read it, I highly recommend that you do. It shows a system of investing that yielded huge returns even during the Clinton "bear market."

I’ve read stories about people setting up ad campaigns and making thousands of dollars within a matter of hours. What’s the catch?  The big one is risk.  You’re spending money to make money, so if you turn out to set up a bad ad campaign that doesn’t convert well, you can easily lose lots of money.  That’s been the primary reason I’ve stayed away from this method of making money online.  I’m not going to bother giving advice here, because as I said, this isn’t something I’ve done.  If you’re interested, you can probably find a lot of good information via Google, but watch out – as with any other internet marketing topic, most everyone is going to try to sell you something.

If you're a graphic designer or even an amateur artist, there are plenty of sites which will pay you for sharing your artwork. Sites like Etsy, Zazzle, and The Souled Store allow people to add their designs to T-shirts, phone cases, mugs, posters, book covers, and more. If and when these products are bought, the sites then pay a commission to the contributing artist.
In 1996, red tape, bureaucracy and the Licence Raj were suggested as a cause for the institutionalised corruption and inefficiency.[377] More recent reports[378][379][380] suggest the causes of corruption include excessive regulations and approval requirements, mandated spending programs, monopoly of certain goods and service providers by government-controlled institutions, bureaucracy with discretionary powers, and lack of transparent laws and processes.
Lending Club is a platform where you can lend your money to other people. You’re the bank. Each note is only $25, so you can invest $1,000 and lend money to 40 people. There are many grades of loan (from safest to riskiest) and investors earn, on average, between 5% and 7% annualized returns. For more information, check out Investing and Making Money with Lending Club Peer-to-Peer Lending and my real money Lending Club Portfolio.
What I’m doing: My realistic goal is to have a blended annual return of 2x the risk free rate. With a current 5% hurdle, I am not paying down mortgages that cost less than 4%. Debt at 5% is a wash. My realistic blue sky scenario is a 3-4X rate of return over the risk free rate which can be achieved with property, stocks so far for the past five years, and certain private equity investments. Where I am dragging is my blended average CD interest rate of roughly 3% from an old CD coming due. I’ve rolled some money into a 12-month CD with CIT Bank at 2.5%. It’s the best rate I can find. 
"Create your own products and services," financial blogger and life coach Michael Tamez tells Bustle. "Any company you could ever work for can replace you at any time. However, your individuality can never be replaced! I encourage you to explore your creative talents and abilities more. What are you good at? How can you monetize that talent and perhaps even build a business out of it? Have you experienced something extraordinary in your life, and because of it, have tons of knowledge and wisdom to share? ... Creating your own products and services can create steady streams of residual income, which pays you continuously, even when you're not working. Essentially, you bust your ass once and get paid for the rest of your life — even when you're sitting on the beach, sipping coconut rum. Just remember this: When you invest in your creative abilities, you become irreplaceable!"

I also noticed that in your passive income chart at the bottom that you don’t include your internet income other than sales from your book. Is there a reason for that? Do you not consider is passive because you are actively blogging all the time to create it? Or do you just not want readers to know how much money you generate from blogging activities?
The Lake Tahoe property continues to be 100% managed by a property-management company. It feels amazing not to have to do anything. I can't wait to bring up my boy this coming winter to play in the snow! I could go up this winter, but I want him to be able to walk and run comfortably before he goes. I've been dreaming of this moment for over 10 years now. The income from the property is highly dependent on how much it snows. Summer income is always very strong.
Retirees are paying a high price as the world stimulates its way out of the GFC (Great Recession).  After a 30-year bull market to the lowest interest rates the world has ever seen, bonds have become highly priced and now don’t generate enough to meet income needs.  Just 5 years ago the average income from $100,000 invested in a 10 year Australian Government Bond (10yrs) was $5,600 p.a.  – now it’s less than half at $2,600 p.a.