I started with a Nelko one for $20-ish, but they have a free/paid system where you don't get all the stickers/fonts unless you pay a yearly fee. Next one I'm looking at is this one that specifically advertises no mtx.

Ultimately the main thing you want is a laser printer with thermal paper. Won't print in color, but it's much less hassle without ink carts and the only thing you'll need to replace is sticker rolls.