Sorry, didn't see any reasonably priced guns on the board at PG. I'll check again next week, as there are new adds weekly.
If all he is shooting is trap, why not get him a true trap gun and not an over under? Bart's has several single barrel trap guns, Brownings and Perazzis.
PG Skeet and Trap sells guns and usually has quite a few and they can help fit. Barts is good but expensive. PM sent