Motorola's Moto G series is usually supported and relatively cheap.
However, if you're willing to spend a little bit more I recommend getting a Fairphone, if you can. Simply because they guarantee 10 years of device support after release and you can easily get original replacement parts.
So you won't have to get a new phone just because the battery died.
So I was about to say "I love my Fairphone 5 and recommend it wholeheartedly but it's not supported by Lineage is yet, which is really frustrating, especially after its been out nearly a whole year", but then I checked and - well, I'll be damned - LineageOS does support the FP5 now so I know what I'll be doing later on: eating chicken wings. But after that, upgrading my FP5 to LineageOS.
Yea it took some time until my FP4 was supported by lineage, back when it was new. But if the price is an issue I doubt OP would get the latest model, anyway.