Kind of like buying a scope. You can spend as much as you want or as little as you want and still manage to get something that works! I do like one piece base's adjustable for windage, I have a couple. I also have nice two piece base's with nice rings and they work very well. I've also had my share of what might be called junk rings and base's and surprise, they too worked! Unless you want something special purpose, the only thing required of base's and rings is to hold the scope in place on the rifle! Now what does that really take? In my experience with junk to nice Leupold and Redfield set's, not much. Go find a set you like and can afford and get them! if you don't like them but they are all you can afford, they will work!
Of course if you have some need for specialty rings and base's, that's different!