BBC News Online Busines reporter
In the third part of a series on investing for fun, BBC News Online looks at the money that can be made from sports memorabilia.
David Beckham models the latest collector's item
For many people it may seem laughable to put the words "football" and "investment" together in the same sentence.
But one area where football has proved a shrewd investment is in the field of memorabilia.
The huge growth in the game's popularity has been matched by growing prices of collectable items.
And football is not the only sport to attract a collectors market with golf, cricket, tennis and fishing antiques all in demand.
But just as football dominates the headlines on the sporting pages, it also provides the leading prices in the world of sporting memorabilia.
"Certainly football provides our biggest sales - the best attended and the highest prices," says David Convery, the sporting memorabilia specialist at Christie's auction house.
And the past few years have seen huge amounts paid for iconic football memorabilia.
The shirt worn by Pele in the 1970 World Cup final went for £157,750 last year, while £91,750 was paid for Geoff Hurst's shirt from the 1966 World Cup final.
But if you've been faithfully buying your team's replica shirts for the past few years, your pile of polyester tops is probably going to generate more static electricity than cash.
The real money is in shirts worn or medals presented to the players themselves - although it is vital to have proof of the item's authenticity.
"If you're going to start collecting now and you've got money to spend I would suggest players memorabilia - the old England international caps, the shirts, the boots etc," Mr Convery says.
And while the debate has raged recently over whether the FA Cup competition is losing its glamour, mementoes from the finals are still fiercely sought after.
FA Cup medals tend to go for between £4,500-£22,000 depending on the player, the team and the year.
Reds in the black
Certain clubs will also attract higher prices and there are no prizes for guessing that Manchester United are the most in demand.
Even at Liverpool auction house Outhwaite & Litherland, Manchester United memorabilia goes for twice as much as souvenirs from the two Merseyside clubs.
Pre-World War II programmes can be very valuable
"If you're buying for an investment, Manchester United are top of the league for anything related to football," says Outhwaite & Litherland's sales manager Billy McMahon.
Christie's sold a pair of David Beckham's boots for £2,350 in 2001 and his shirts can fetch between £700-£2500.
But if you don't have much cash to spare, David Convery advises starting with more humble items.
"If money's tight, start with the programmes, ticket stubs, lapel badges - in time they will increase in value."
Ticket stubs have become increasingly collectable as most fans throw them away after games.
A complete 1923 FA Cup Final ticket - the first final to be held at Wembley - sold for £3,200 a couple of months ago.
But if you are lucky enough to be going to an FA Cup Final the key is to keep everything together.
Depending on the year, an FA Cup final programme, ticket stub and song sheet together can make anything up to the high hundreds or low thousands of pounds.
Par for the course
While some fairly recent footballing items are starting to attract good prices, with other sports you have to go back much further.
In golf, the really big money lies in clubs from the nineteenth century and before that.
This golf book from 1842 sold for £9,400 at auction
Long-nosed, or 'scared head', clubs can be worth thousands of pounds each depending on who made them, with the record price being £106,000 paid for a club from the eighteenth century.
The market for tennis collectables is "growing tremendously well" according to John Mullock, partner at sports memorabilia specialists Mullock Madeley.
Old and unusual items will fetch the best prices - an early tennis racket from the 1880s can reach between £1000-£2500 according to Mr Mullock.
The market for fishing related goods is also expanding, helped by the wide range of accessories the sport produces.
Mullock Madeley recently sold a limited edition 1930s fishing reel made by the manufacturer Hardy for £10,000.
In general though, football memorabilia dominates the market and appears likely to for the foreseeable future.
But if football's bubble bursts - will the shirts, medals and boots accumulated prove to have been a poor investment?
John Mullock thinks the simple laws of supply and demand will continue to underpin the market.
"I think football items will remain a good investment because the modern day footballer will never need to sell them," he says.
Many former footballers have sold personal items to shore up their finances, something today's multi-millionaire stars are unlikely to have to do.
"Can you imagine David Beckham having to sell one of his FA Cup final medals?" says Mr Mullock.
On 18 August the fourth part of the investing for fun - making money from art - will be published.