Stillwater Kilts are excellent...and if he's 18, he's liable to be a bit active and hard on them, so get something you (or he) can afford. If his size is there, then he'll have his kilt in no time at all! A dressier kilt can come later. If you go this route, don't forget the belt, the sporran, and the sporran belt.

Utilikilts are also sturdy, though a bit more expensive, but they don't come in tartans.

from both southern US coasts!