Amazon has a good number of various kinds of resistance bands, as well as sets that include handles, door anchors, ankle straps and a carrying bag; most sell for under $30 so no big loss. Not all bands tear or stretch easily unless they’re extremely flimsy or they’re not being used correctly (usually being stretched to more than 2.5 times its resting length); some don’t stretch as far as others.
These are also great bands, and the education component is great. Dave “the band man” was one of the original rubber band educators and is a physical therapist. I’ve got several sets of these bands, too.
What I tend to do is wait until I need bands and then see what is the cheapest for my current need.