If you're one of those people who doesn't take things out of boxes and keeps them in mint condition, I'd say "You go girl, you can always sell them on ebay.", if you're like me, which means you're tactile and want to touch them. Just don't.
I have to control myself with anime DVDs, the other day I was staring at the Nana DVDs and bought four on a whim.
These days I still spend a lot on merchandise, but usually it's something that has a usage, so it's books or cds or dvds (or of course, MAKEUP).
I stopped buying the collectibles because it was a waste of money, the only thing I regret not buying is a LE Phoenix statue with the Phoenix Effect in smokey flamey glass, GODS I'm a sucker for Jean Grey... but I digress...