Hairy's completely correct.
War gamers. RPG gamers. Comic-book enthusiasts. Doll collectors. Car collectors. People who show dogs/horses/geese.
Really, anyone who collects things or has any kind of expensive hobby (or even a cheap hobby!) has probably heard that comment, or a variant on it at some point in their life and the right answer, if you don't just shrug and smile, is, 'It's my money. I happen to like *item*. 'Nuff said.'
I collect dragons (of all kinds; statues, plushies, beanies, kites), resin dolls and I have a plethora of other hobbies and interests. I don't have to justify /any/ of it to anybody.
Neither do you. It's your money and time. You spend it the way you want to.