I remember, as if it were yesterday, the day in 1986 that I bought my first rock T-shirt. The band was The Smiths, though the face on it was Oscar Wilde's, one of Morrissey's heroes. By wearing it I was not only pledging my allegiance to a group, I was telling passers-by the kind of person I was. What didn't occur to me was that I'd turned myself into a sandwich board, providing free advertising.
Merchandise has always been big business though, in the age of illegal downloads and plummeting record sales, it accounts for an ever-growing percentage of a band's income. Rare is the gig that you don't see trestle tables awash with T-shirts, keyrings, pens, stickers and posters. A touring stadium act can make almost as much money selling programmes, posters and T-shirts at the venues as it can from tickets. Hair metallers Kiss are the market leaders here: two decades after their last hit they continue to do a roaring trade in condoms, comic books, cheque books, clocks, bowling balls, number plates and, yes, laminated steel coffins (£2,600, if you're asking).
Kiss took the concept of pop merchandise into a whole new stratosphere. Bands are now required to come up with ever more imaginative products: Belle & Sebastian are flogging embossed frisbees while Keane, in keeping with their woolly sound, have designed their very own fleece scarves. Perhaps the most unusual souvenir comes courtesy of Peaches and her novelty pubic wig - a snip at £12.
The business of pop merchandise goes way back, of course. Beatles souvenirs took in everything from dolls and beach towels to novelty mugs and jewellery. But in the last decade it has honed its skills, targeting specific age groups.
In particular, the music industry has identified tweenies as a rich source of revenue: five to 13-year-olds now make up the lion's share of record buyers. No wonder, then, that the manufacturers of children's toys Mattel have announced that they will continue plans for their Destiny's Child dolls. The fact that the band are due to split in the autumn apparently doesn't pose a problem.
Now no band is complete without its own ring tone, or a DVD of their latest world tour. And where there is a chart-topping pop star, you can be sure that a biography will follow. Madonna, for example, has produced any number of picture books and biographies.
In recent years musicians have learned to set their sights a little further. Star-endorsed energy drinks and own-brand fashion labels are increasingly fashionable in the US. Women in pop are also wising up: Gwen Stefani's solo LP, released this year, seemed little more than an advert for her fashion range - they even had the same name.
Last year, Kylie Minogue added lingerie to her catalogue of must-have merchandise, though the big money is more likely in the calendar in which she models the collection.
The days of commercialism and creativity as separate entities are clearly gone. As fans are happy to promote bands by wearing their T-shirts, artists are equally comfortable with advertising commercial products.
Think Madonna and Gap, Britney and Pepsi, Justin Timberlake and McDonalds. Eyebrows were raisedwhen Bob Dylan announced an exclusive deal with Starbucks, allowing them to stock CDs of a long-bootlegged concert at New York's Gaslight. So has Bob sold out? That depends on whether you think the grizzled one is best enjoyed with an extra-large skinny latte.