I bought a used Prusa i3 which came with some spools of filament. I'm at a point where I want to buy more. None of the existing spools have any useful markings on them, so I can't just buy what I've been using.

Looking for recommendations for regular PLA 1.75mm filament.

I'm assuming that when I switch filament manufacturers that I'll have to go back and re-test hot-end and bed temperatures all over again for best prints. So I want to start with a source that will continue to be around. And obviously cost is a factor.

Or am I making more of this than I need to and just go on Amazon and get something?

Thanks.