really, whatever you get will be too fragile to go with the oscar in a year or so. what you could do, however, is find out if your LFS has any fish they would buy back from you at a larger size. Fish like Angels and Black Skirt Tetras fetch a much nicer price when full grown but take a lot of time and feeding to get there. If you can make an arrangement where you know you can return the fish for at least as much as you paid for them, you might want to take advantage of that. you'd win by getting some pretty fish for a while; the store would win by having someone to grow their fish out for them.