What: Since the first Beano, issued in July 1938, comic books have been hugely popular collectibles.
To buy: New comics retail from about €2.50 to €4. Older comics, particularly those featuring well-known superheroes (Batman, Superman and all their pals) can fetch thousands, depending on the issue and its condition.
To sell: If you get your hands on a new comic that happens to sell out quickly, you may be able to sell it on for three or four times the face value. If you have a near-mint condition Issue 1 of the Amazing Spiderman, published in 1963, it's worth about €28,000.
Best buys: Issue 1 of a series; the issue in which a favourite character first appeared; a guest appearance of a character from another comic; a set of issues where multiple covers were produced; and issues with a limited print run.
Pitfalls: comics are flimsy things. Once bought they need to be bagged straight away to preserve their condition. Natural light and damp are comic killers.
What the expert says: "Anything to do with the 1980s is very big right now. Transformers, Battle of the Planets and Thundercats comics are all selling out very quickly" - Kevin Lyons, Forbidden Planet.
Contacts: Comics International magazine is probably the best of the trade magazines. There are also innumerable websites devoted to the subject.