"Real Estate books" aren't bad. I would strongly suggest that the OP do as much reading as possible. Self-teaching is incredibly efficient. For example, here is a book from one of the BiggerPockets guys. Though yes, avoid classes and any books greater than like $50.
I think he’s talking about this one, I’m on my first read through and it’s been a great read. I also listen to every podcast they put out! Love BiggerPockets
https://www.amazon.com/Book-Rental-Property-Investing-Passive-ebook/dp/B018UTI2DO/ref=nodl_
IMO dont look at low income rentals. Evictions and maintenance calls will wipe out all of your profits. Depending on your area, you should be able to find some single family homes in decent areas (decent school districts) that need to be fixed up where responsible people want their families but don't quite qualify to buy a home there. The BRRRR (Buy, Renovate, Rent, Refinance, Repeat) method seems to work well in these areas. I've got a rental in an area like that. Its been rented for 3.5 years straight to the same tenant. Only get a maintenance call once every 6-9 months for things that actually need to be fixed. They always pay on time. It also cash flows nicely. I'm averaging 17% net profit each month ($240 per month). I fell into this by accident when we needed to move but couldn't sell the house at the time. After doing alot of research over the last year, I realized we did it right. The book below helped me realize this. Might help you with getting started. Theres alot of pushing you to biggerpockets.com in the book but you may want to check that out also. https://www.amazon.com/Book-Rental-Property-Investing-Passive-ebook/dp/B018UTI2DO/ref=sr_1_2?ie=UTF8&qid=1490583375&sr=8-2&keywords=biggerpockets
My favorite has been The Book On Rental Property Investing by Brandon Turner. It's pretty good if you don't know much at all. He shamelessly promote his website every once in a while but I do think it's a pretty good read.