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.
You’re right Ed, it does require capital to get income from a rental property. However, I started hustling when I was a teen, baby-sitting, teaching younger kids the piano, doing homework with middle schoolers, being a French and Spanish tutor, none of which requires an initial investment. As do pet sitting, housekeeping, lawn mowing, house painting, and many gigs around.
Find the thought leaders in your particular industry, and find how what they’re saying about the industry. Many thought leaders put out white papers, free webinars and other useful information to attract an audience- and potential future clients. The information must be useful, in order to keep the reader engaged, and it can be a great reference for you.
Investment in real estate can also be a source of a second income. If you have a decent sum of money lying around, you can use it to invest it to buy your second home. You may even take a home loan to finance your second home. This can become a source of income for you when you rent it to someone. These monthly rents would become your secondary monthly income. The key to making more money with rental properties lies in buying smart. Not all kind of property is going to give you a good return. Hence, analyzing the potential real estate opportunities is very important. The monthly rent highly depends on the area/location of the property hence it is highly important that you select the location of your property very wisely, keeping in mind the rent factor. You can save much even after your home loan EMIs. In addition to this, you can also avail tax exemption on the purchase of your property if it is through a home loan.
San Francisco is an extreme example of a place in California with both a large population (829,072) and high per capita income ($49,986). In fact, it has the highest per capita income of all places in California with a population of over 100,000. Though Sunnyvale ($48,203), San Mateo ($46,782), Thousand Oaks ($46,231), and Carlsbad ($44,305) join San Francisco to make up the top five places in California with the highest per capita income in that population class, none of them have populations even close to San Francisco. The next place with a population similar to that of San Francisco that appears in the per capita income rankings is San Jose ($34,992), and at this point, the difference in per capita income with the entire state of California is only about \$5,000.
Audiobooks are witnessing a surge in popularity when compared to their text-based counterparts. If you have decided to write and publish an eBook, converting it into an audiobook requires little effort and is a great way to bolster your income. Amazon's Audible ACX platform connects authors with producers who can turn their written work into professional grade audio. Once that's done, the audiobooks are put up for sale on Audible and iTunes.
Online learning platforms have become extremely popular in recent years with people using platforms like Coursera, Lynda, and Udemy for learning courses about their specific interests. If you are knowledgeable in any field, whether it's web programming, photography or digital marketing, you can create a course on platforms like Udemy or Unacademy and earn money when users register for them.
Portfolio income can come from multiple sources – interest/bond coupons, stock dividends, financial strategies including derivatives and capital growth.  Each offers some cash flow and some also offer potential capital gain with some risk from liquidity and volatile prices.  In this low-yield environment, many investors rely too heavily on cash flows and to pursue this are venturing further into riskier areas than they’d normally consider.