So I started by inheriting an Ender 3V2, which I believe in a sale you can get for something like $150, downsides to that one are the fact that you have to completely assemble it yourself and it's going to be prone to levelling issues, and for me it was just constant pain ... but it can slam out some good prints
I just saved up and got a Creality K1 Max, which was literally open the box, run the diagnostic, and start printing.
Honestly I would go in the middle and get a Creality K1, it's got all the same auto bed levelling features, and will save you a lot of pain over one of the build it yourself ones, but will save your wallet comparable to a bambu.
As for models, there is a VAST network of sites providing both free and paid models for printing