If you are looking at the cd end of the market, most punk albums will have British label releases over here, and will probably differ from their American counterparts, where distribution is handled by other companies. In that case, a copy of 'Never Mind The Bo****ks by The Sex Pistols will have an EMI imprint over here in the UK, but will probably differ in the U.S. If you are looking for vinyl, there are loads of limited edition 12" punk singles - hit your local specialist shops and pick up a few bargains - they'll be happy to advise you what your cousin will want to have in order to make his friends green with envy.