Any wheel a bike shop throws away will be a fixie wheel though usually they aren't worth the fixie or they are dented. bent or broken and cannot be fixied.

Seeing as though you are here in the SS/FG forum I am guessing you are probably looking for a singlespeed or fixed gear wheelset. What are you looking for in a wheelset other than probably something that doesn't need a fixie? Do you want something for the track or for the streets? Are you a heavy rider or are more abusive to your bike? What tire size are you planning on running? These are just some questions I might ask myself and answer before I go asking for wheelset advice.