Ziggy played guitar - and now you can own it Stephanie Connell of Bonhams said "items related to David Bowie seldom come to market" - largely because the singer and his archivists have kept many such items themselves. So this is a rare opportunity for collectors and investors. The Entertainment Memorabilia auction - which is held twice a year - also includes a guitar owned by Jimmy Page, the lead guitarist in Led Zeppelin, and a canvas painting by Radiohead frontman Thom Yorke. There are also photographs, signatures, platinum discs and other "ephemera" related to the Beatles, the Rolling Stones, Jimi Hendrix and the punk movement. While the most popular lots in this week's auction will be sold for tens of thousands of pounds, you don't necessarily need to have significant savings to make a credible bid. Some items are expected to sell for between £200 and £1,000. Over the past 20 years there has been a significant increase in the number of people collecting such items. While there are serious investors prepared to part with six-figure sums for a prized item, they are also vying with keen music fans who will pay good sums of money to buy a cherished guitar or rare vinyl pressing associated with an influential musician. Memorabilia can cover a diverse range of items. Recently one of Lady Gaga's acrylic fingernails sold for a surprising £10,000, while John Lennon's rotten tooth sold for $31,000 (£20,000) last year. But typically items for sale will include concert programmes, signed photographs, musical instruments, lyric sheets and musical notation, and the costumes and clothing that have been worn by a pop star or band. Ms Connell said: "The closer the item takes you to the music, or to a live performance, the more valuable it is likely to be." She said lyric sheets, where fans can see the song being worked out and written down for the first time, tend to be most valuable. Adrian Roose of Paul Fraser Collectibles said: "While Beatles lyrics can sell for millions, we've seen lyrics written by Phil Collins, Mick Jagger and Madonna fetch between £5,000 and £20,000." Clothing that has become iconic - think Michael Jackson's glove - can also command high prices. Recently a George Harrison jacket from the Hamburg era fetched more than £90,000 at auction, while Freddie Mercury's harlequin stage costume raised more than £20,000. But it is musical instruments or cars - which are often expensive items in their own right - that fetch the highest prices at auction if they are linked to a famous rock or pop star. George Michael famously bought John Lennon's piano, used in the Imagine video, for £1.6m in 2000, while Lennon's psychedelic Rolls-Royce Phantom V, which sold for £2.2m in 1985, remains the most expensive piece of rock memorabilia ever sold. The Beatles retain premier league status among collectors. Ms Connell said: "There is always a huge number of buyers globally who are interested in items linked to the Fab Four. This has created and sustains a healthy market in Beatles collectables. Mr Roose agreed, saying: "The Beatles and Elvis are perennial favourites. They are the 'blue chips' of the collecting world. But items associated with other Sixties icons also fetch good prices. Mr Roose said: "We have seen an increased interest in the Rolling Stones lately - and recently sold a signed guitar for £5,950. The biggest price move in recent years has been on Jimi Hendrix memorabilia - whether it's worn clothes, signed albums or even simply signatures. Auction prices for these items have increased by 20pc in the last 12 months. Ms Connell said items related to rock stars such as the Who, Pink Floyd, Led Zeppelin, Queen and Eric Clapton also sold well. However, there is increasingly a market for items associated with more recent stars, in particular the punk movement, as well as Eighties stars such as Michael Jackson. The most collectable artists all enjoyed the combination of commercial success and critical acclaim, and have been credited with influencing other artists. What is often key is that they have been global stars, so there are collectors in many countries looking to buy these items; this can help push up prices. Do these same rules apply when spotting which of today's pop stars will be coveted by tomorrow's collectors? Ms Connell said: "What we collect might change. Photographs used to be a rarer commodity, as were cine recordings of many concerts, so these have value. Today, this is not the case. These images will be shared, concerts are uploaded onto YouTube and most are professionally filmed now anyway. But she said the same rules might apply when deciding which bands will be deemed as "important." We are already seeing some interest in bands like Coldplay, Radiohead and U2. There was also a recent auction in Stockport of items associated with some of the leading Britpop bands of the early Nineties, such as Oasis, Primal Scream and the Stone Roses. Items were donated by a record label boss who claimed he was "clearing out all this rock 'n' roll rubbish from my house." But there is clearly growing interest in such items. In many cases it is about timing. Collectors tend to be in their forties and fifties - you need to look at which bands would have been important to them 20 years ago. When buying memorabilia, provenance is everything. The items sold at respected auction houses should be properly authenticated, and they will have specialist valuers who can, for example, spot a fake signature. Part of the process is asking how an individual selling such items came to own them. Prized items often come from those who have unique access to a band or artists: perhaps a technician or those working for record labels. Equally, those working in hotels or concert venues can accrue a wide range of items that together can be worth significant amounts. There is no shortage of people purporting to sell such items online, although buyers don't have the same safeguards. A quick scan of eBay last week unearthed a guitar signed by George Michael (for £495), signed Rolling Stones pictures (for £96) and for £15 a signed Guns N' Roses T-shirt. Between the auction houses and eBay sit a number of dealers that specialise in rock 'n' roll and film memorabilia. Again, they should provide certificates of authentication with any items, but you tend to pay a set price rather than bid for an item. Those dabbling in these areas should take valuations with a pinch of salt when weighing up investment potential. Just because certain rare items connected to the Beatles have doubled in value in the past few years, it doesn't follow that Lady Gaga's fingernails or a signed Rod Stewart picture disc will see the same appreciation. As with other "alternative" investments you are better off buying something you enjoy owning. If it also turns out to be a shrewd investment, then enjoy your gains too.