You might like Anna's archive. It isn't a quick way to get heaps of ebooks, but I bet you can download them faster than you read them. Haven't kept up on e readers in the last several years, I'm sure you can find a decent one on your own though. Avoid Amazon on general principles, and the kobo ones have Walmart integration FYI (bad)
Piracy
Arr
Join my Myanonamouse. They have the largest collection of ebooks and audiobooks. It's 100% worth it. You can find nearly any title you're looking for on there. You can only join during a certain weekly window, and have to pass a test that is based on their rules, but it is absolutely worth it, my friend.
I did this and with no real experience, everyone there was and is extremely helpful and the material is excellent!
Yeah. Anonamouse is super rad. If you don't already have one, think about getting an external HD and have it just for anonamouse torrents. You'll get all your bonus points fast.
Are you open to audiobooks? I find I can listen a lot more often than I can read. There's a few good recommendations already here but for audiobooks, Audiobook Bay is pretty good.
oceanofpdf.com
Mobilism dot org and myanonymouse
I've never not been able to find what I want