I got a pair of c-quest lineage clowns directly from a breeder. They were (and still are) very young. Some of their deformities are just starting to come to light a little bit but they aren't that bad. Typically a C-Quest clownfish will go for around $69-$125 each.
If you look up Rod's Onyx clownfish, the original pair (especially the female) was very deformed. Yet it produced some nice babies. A small underbite here and there isn't a big deal. However, as D-Nak mentioned extreme overbites and square heads should be avoided.