You don't need new glasses each time you need the prescription updated, you can just have new lenses put in the current pair if you want. I've had my glasses 20yrs for one pair 10yrs for two others. They cost £80-150 each.
I find cheap ones don't last longer than around a year, the frames come loose and need constant tightening or the lenses fall out, plus the paint chips easier.
Consider whether you also need sunglasses in your prescription as well as plain ones.
How blind are you naturally? This is a factor in whether your glasses need to be a different colour to your furniture/floors.
Do you need them for driving and do you need to drive? If so then definitely have a second pair even if it's sunglasses, if one pair breaks you don't want to be stranded until you've got a repair.
Consider the colours you mostly wear as well as what suits your skin tone to make sure they'll work for most outfits.
You don't have to buy from the place you get your eyes tested, you can pay for the test then ask for your prescription and take it wherever, so you won't need to pay for an eye test at wherever you decide to buy from.