My boyfriend and his buddies have been trying to recapture their childhood lately I guess by buying the Marvel superhero card sets they had (or just wanted) as kids. To store the cards, they've been going to the local comic store to buy these little plastic cases that hold a good-sized stack of cards. While I'm no card collector (except for cards related to tri-Ace games :P ), the size of the cases intrigued me... The width and height appeared to be nearly EXACTLY the same as a GBA cart. Lo and behold, when I tried it out, it worked perfectly. They can hold around 10 carts (a guess, because I don't even have that many GBA carts yet). There's a little space on the top that a couple more carts could possibly go, but it looks nicer as just a plain row. Later on, my boyfriend picked up a case for even larger stacks of cards, and yet again I got curious. They work just as well for original Game Boy carts. :) Loose carts only, though. They're too snug to fit the carts in their cases.
The great thing about these cases is that not only are they really tight, compact storage that looks nice and keeps the games clean, but they are also perfect for travel. While they can crack if you really give them a beating, they should hold up very well in a backpack or something else of the sort. The flip-top lid holds quite tight, so it shouldn't be much of a worry that they'll all spill out. I'm definitely going to use them on my summer vacation. I hate a big mess of loose Game Boy carts, and I'm always paranoid that I'll lose a game (especially with those tiny GBA carts). Best of all, these cases are CHEAP. 50 cents for the GBA-sized ones and a buck for the original Game Boy game-sized cases. Of course, the prices and cases may not be some national standard, but go see what you can find. :)