Many drug stores carry them. No way to say what any particular store carries might be good, bad, or somewhere in between but you can get your hands on them and judge their relative quality. Go to enough drugstores and examine enough of them and you should be able to gauge relative merit. Buy a few pairs, they are pretty cheap, and put them through their paces.
First pair I had I went around cutting all sorts of materials to get a feel for what they could do. I cut a nice 6" hole in a car door by jabbing the pointed blade in and cutting in a spiral. Impressed the hell out of me. I worked them abusively until the blades were dull and sprung.
Then I bowed the blades back, used a side grinder to resharpen them, and peened the rivet to tighten it up. They worked pretty well. Not as well as when new but good enough to reliably cut tape, gauze, cloth. As I remember it they are in one of my give-away kits. What can I say ... I'm cheap.