Malcolm Phillips, who runs Comic Book Postal Auctions, was responsible for selling the Dandy number one. "We've been going 14 years and the market has changed enormously - in 1999 a Beano number one got the then world-record price of £6,800, but this had risen to £12,100 by 2004," he says. "These are collectables people can enjoy without being knowledgeable about the subject."
Although the first Dandy came out six months earlier than the Beano, in December 1937, it usually does not fetch as much money. The £20,350 paid was for a fine-condition comic which included the original free gift. The Express Whistler toy, a whistle made of tin-plate, is the only known gift to have survived.
It's not just the first editions that are rising in value. "Prices have changed enormously," Phillips adds. "Beano and Dandy from issue 20 onwards used to fetch £2 to £3 an issue, but now they can top the low hundreds. Even those from the 1950s used to make just a pound a piece, but have doubled or trebled in value."
It is the rarity value of the early issues that drives their prices so high. The Beano and Dandy were launched before the Second World War. During the war years people were encouraged to give up comics and newspapers for recycling for the war effort, so very few survived. Likewise, issues from wartime are scarce as few were printed, often on very poor quality paper and generally with fewer pages.
In fact, wartime comics are an interesting subset of the comic market as they were often used as propaganda vehicles. Strips such as Addy and Hermie (Adolph Hitler and Herman Goering) and the politically incorrect "Musso the Wop" about Mussolini are part of our social history. Meanwhile, mainstream comic characters such as Desperate Dan were fighting Hitler - issues with these wartime strips are more sought after.
From the 1950s, Beano and Dandy still dominate, though in March 1950 The Eagle comic came out and a pristine first issue can sell for £800 or more in fine condition. Low-quality copies go for more like £60 to £70.
A few years later, DC Thomson launched Topper and Beezer - two broadsheet format comics - and these are all the more collectable today because they were damaged easily. A first edition of a 1953 Topper or 1956 Beezer could make £150 in fresh condition.
In the 1960s, one of the iconic comics was TV Century 21, first released in 1965. This included Thunderbirds and Stingray. The number one issue came with a free gift of a secret agent decoder - an example with gift and in good condition could make £200 plus.
Find a first edition Beano or Dandy in the attic and you're on to a winner, but you're unlikely to get a bargain copy at a boot sale, because people know that these comics are collectable.
However, as we all age, different eras become more important. In 1973 2000AD came out and it was the first comic to bring in a futuristic world of conceptual stories, including Judge Dredd. The first three issues with their free gifts can sell for up to £500 to £550 each in very fresh condition. If you are buying for investment, buy only copies in fine condition and preferably with any free gifts still intact.
One area seeing a rise in interest is girls' comics. Women have traditionally represented a tiny part of the collecting world, but a brief look on auction site eBay suggests this is changing. Early issues from the 1930s and 1940s are already sought after, while Bunty, Mandy, Tammy and June readers from the 1960s and 1970s seem to be increasingly interested in reliving their childhoods.
Even the more magazine-style Jackie is selling at several pounds each for 1970s editions. Phillips says: "These are strongly undervalued as a first issue of Bunty or Tammy can go for just £30 to £40 with its free gift."
Also consider bound volumes. At one time, serious collectors would not consider them but they are making comics more accessible. "Bound volumes are increasingly popular because they take comics from the attic and basement and promote them to the living-room or lounge bookshelf."
There are two important offshoots of comics- annuals and original artwork. Annuals follow the same rules as comics with rarity and condition dictating prices, but original artwork could be the best investment of all as these pieces really are one-offs. "The value of comic artwork is on the rise but only for characters who are recognised in annuals such as Beano and Dandy, The Broons and Oor Wullie," says Phillips.
"Any artwork of Dan Dare is pretty valuable, for example, and sells for in excess of a £1,000 a page, but I couldn't get more than £30 to £40 for Billy Bunter from the 1930s and 1940s because the character is no longer interesting."
Comic Book Postal Auctions: 020-7424 0007; www.compalcomics.com