Used Books + Amazon FBA = goldmine... i tried this method after reading everything on this blog
FBA (Fulfillment by Amazon) Mastery | Selling books with Fullfillment by Amazon (FBA) . Basically what you would do is scan books at your local thrift stores (Goodwill and Goodwill Outlet are the best ones for low cost books with high margins) and see which books will sell for profit (you use amazon seller app to scan the books and see what the books sell for on Amazon).
A lot of these books wont cost you more than a dollar (i paid about .30 cents a book) and a lot of these books will sell for 15+ (especially textbooks). Tried it out in late August and got about 250 profitable books from goodwill outlet (paid like $65 total) in the course of a couple days (only spent 1-2 hours there a day). Sent them in to Amazon and sold about 90 my first month for about $1,400 total ($800 profit after amazon fees, book cost and shipping costs). To date I made over $1,000 profit for like 8 hours of work max (scanning the books and packing them to ship out to amazon)..
I dont do it much anymore because im focused on other categories and christmas sourcing so i figured id drop that for yall to eat. Gonna go crazy with it myself once the new year hits.
cliffnotes:
1) find profitable books from a thrift store
2) ship said books to amazon fba
3) sit back and enjoy profits