Many toys or games are collectable, whether for financial gain or just because the owner has fond memories of the toy from their childhood. There are many conferences that go on all over the uk where people can show off their collections to other avid collectors.
Toys which have a high value attached to them have to be in a good condition, and to get the top end of their value, need to be unused and in their original packaging. This is why such toys demand high market value as there aren't many out there which haven't been opened and played with at some point during their life time.
Tonka toys are another old collectable and are based around toy cars, vans or trucks. Many of the most desirable Tonka toys were made between 1947 and 1963. Their value is determined by their condition, such as rustiness, battered, pristine, in their original box or just the plain rarity of the item.