Thanks for writing this Mr. Samurai. I just got over the student loan hump but I feel pretty good about it at 27 having a graduate degree and being 100% debt free. Now that I’m on the other side it is good for my brain to absorb some of your knowledge regarding passive income investments. I love gleaning wisdom from older folks who have been there and done that. Mentors rock!

Making legitimate passive income isn’t as difficult as you might think. Some of the best passive income ideas might take a little time to set up but can start cash flowing within a couple of months and will provide a consistent monthly income for years or more. The most important point is just to get started. You make exactly $0 on the passive income sources you never start.
Right now, I’ve got my day job, some index funds, a small income from my blog (about a penny a day so far – ha!), and some knitting patterns I designed and have for sale at various sites around the internet (not surprisingly, that doesn’t bring in much either). Eventually I’d like to write an ebook, although I have no idea what the topic would be yet. I’ll keep plugging away and hopefully it’ll become clearer in the future!
You must sacrifice the pleasures of today for the freedom you will earn tomorrow. In my 20s, I shared a studio with my best friend from high school and drove beater cars worth less than 10% of my annual gross income. I'd stay until after 7:30 p.m. at work in order to eat the free cafeteria food. International vacations were replaced with staycations since work already sent me overseas two to four times a year. Clothes were bought at thrift shops, of course.
Realtyshares is pretty cool. It allows you invest alongside other real estate investors in smaller increments than traditional syndicated investments. You typically invest in debt (tax liens) or equity (take a small ownership) in exchange for putting up capital. Rates can vary from 6% all the way to 19%. There are certainly risks, but that’s what’s great about it… you can spread it across several investments. I’ve done about a dozen deals with them over the past 2 years and so far so 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. 

In 2017, I ended up deploying roughly $611,000 into stocks and $604,327 into municipal bonds. The stock allocation should boost dividend income by about $12,500 a year, and the municipal-bond portion should boost income by about $18,000 a year after tax ($26,000 pre-tax). Therefore, total passive income gets an about $38,500 lift, which recovers over half of my $60,000 loss from selling the house.
In addition to opening a brokerage account, you can also invest in peer-to-peer lending firms like Lending Club. I’ve been using Lending Club for a few years, and my net annualized return was 6.02% percent last year. Picking the right investments is easy since the platform offers automatic investing, but you can also pick your own notes if you're brave and want to learn the best ways to leverage the Lending Club platform.