Being a trendsetter can be pricey. As any fashionista or gadget hound knows, the latest frocks and tech toys don't pay for themselves. But a new Web site is trying to make it profitable for music lovers to stay ahead of the curve -- by paying them when other people purchase MP3s they've bought. Berkeley, California-based Popcuts, which publicly launched its Web site in early August, charges users 99 cents per song. Thereafter, whenever someone else buys the same song, those who have already bought it get paid in credit that can be redeemed for more Popcuts music. The earlier you buy a song, the larger your cut of future sales. And while credit is currently the payment option, the site's founders hope to eventually pay users in cash, too.