Z-lib.org goated website for book archives its got everything. What I do is I read the book digitally and if I like it I'll buy the hard copy. I would recommend going on reddit to the suggestmebooks sub reddit and either make a post based on genres and/or interests or browse to see if anything catches your eye.
Depending on what genres and things you like people can help you out. One of favourite books is Catcher in the Rye, it's a out a teenager who is having tons of personal problems and he's trying to get by day to day life facing them. Loved it but others can find the main character annoying.
Psychological thriller I recommend YOU it was pretty good with an interesting way of story telling that focused on heavy narration in the first person pov. About a guy who becomes infatuated with women to the point of stalking them.
Stephen King is goated at horror especially his old works. A really light read I recommend is Apt Pupil. It's about a teen who is interested in Nazis and blackmails his ex nazi neighbor to telling him about the atrocities he committed. I like it because of the descent on madness that this kid experiences as the book progresses.
Animal Farm is a satirical take on the human mind and how people will always manipulate one another to get what they want. Except this time it's animals in a farm. Light read easy to follow and digest and overall good book.
No longer human is amazing but feels like a fever dream. It's hard to follow along but it's about a guy who doesn't know his place on life, but rather than trying to figure it out he just lives life without viewing himself as human ever. Breaking his psyche even more. Wouldn't recommend starting with this.
Those are some of the books I have really enjoyed so if you do check them out it would be cool, but it's all a matter of taste, read what you like :)