ever bought bundles of kindles books of ebay

[Eve]

trying to decide if these are worth it or not? or legal?

and avoid being conned into buying the books that are free anyway.

I'd say they're not legal - I don't think there is a legal way to resell ebooks. And if you're not bothered about legality ebooks are easy to find for free anyway, although this is of course a breach of copyright.

Project Gutenberg is a great legal source if out of copyright ebooks,