The question(s) is a bit vague... we need some more info. What fish do you have in your tank? What size is your tank? Is this a reef, FOWLR, FO? How established is the tank?
I'm not sure about price range (try Google) or how well these particular dwarf angels do in captivity, but in general Centropyges have a reputation for hunger strikes. My advice is to make sure the fish is eating before you purchase it, and that the tank is well established with perfect parameters. For more specific info, try the fish forum - hopefully someone there has this fish and can give you more info
