A number of games can be picked up very cheaply – a cheap board game such as Trivial Pursuit may be picked up for about £ 3. But considering the fact that people always want questions and a medium sized game may have over 1000 questions in it, it is more profitable to sell the question cards in packs of 50 or 100 or whatever.
Of course not only Trivial Pursuit is the only game with questions but of course a popular type of quiz game which people would search for.
Special playing pieces may also be collectable-such as gold version of Monopoly or Clue are also collectable. as well as special novelties versions of the game, but of course the whole thing is a great deal more collectable. Doing some research, looking at completed listings will help you work out what a particular item is worth. Of course once you take pieces out of a game, it is no longer complete and can not be sold as such.
Antique board games are particularly collectable-such as Mah Jong (which is the preferred spelling only Mah Jongg is also correct). However the more obscure the game the less likely it is to be searched for-finding a private dealer may be preferred. For instance how many people would run a search for halma, or merelles? Even if you no longer have the pieces for a game the boards themselves may be considered reminiscent of childhood.
Another item worth looking at is packs of cards. Of course simple packs are worth next to nothing, but if they have a famous designer on the back, or they feature a special TV / film character or historic people they are worth much more. The trouble is that cards in a pack do go missing-this is important if they were used as playing cards or placed in a display.