Dude honestly, no 1 method is gonna help you if you don't have money to lose. Forget "money to invest". Starting out, just consider it "money to lose". If you don't have money to lose you need to play it safe.
I started by designing Wordpress websites. After I built my first one (and it was shit) I blasted CL and scoured for people looking for web designers. Starting out I was charging $250-$350.
Now I get $1,750 on average and have received up to $4k. That's nothing. I know B2B marketing agencies charging $50k+ for WP websites. Fucking insane! But the other work that came from it and the connections are priceless. New websites always bring up new inquiries. "Do you do SEO?" 'Can you refer me someone for AdWords?" etc etc...
Wasn't too long before I began saying "Yes!" and literally skipping sleep every other night (working 40 hours straight and sleeping 8 hrs) to learn what I needed to make the client happy. In retrospect, I was getting paid to learn. Can't tell me that doesn't beat going to college.
None of it was generating an income at start though and I was doing A LOT to stay alive.
Retail arbitrage Amazon/Ebay
Kindle Publishing
Had a blog
Reselling services on Fiverr
Finding vintage books at thrift stores and reselling on Ebay and Abe
Affiliate (reviews on YouTube)
And a few more I'm forgetting about. But when I was doing all of this at the same time, it was nice because I was making money on my own. But it sucked and it wasn't a lot. Was barely paying bills and eating. I was spread far too thin. But I learned what I needed and now I'm good.
There might be a method here you can start and make money immediately somewhere in the forum, but I've always had to use the knowledge gained from reading several methods here and kinda create my own shit.
Shit, outsourcing and reselling services in this very forum has made me a nice chunk of change.
Wanna make money? Use your brain and hit the gas.....