Best type of bag for passporter?

[PrincessTeddyBear]

I recently bought the Passporter Deluxe for our trip to WDW but now I need to find a bag - preferably a backpack to carry it around in. Does anyone have any suggestions for something that's not to expensive and preferably in black? I thought about my backpack from when I was in school but it's huge and I don't want to be lugging it around all day (the backpack not the passporter!).

 

[etwinchester]

I purchased the Disney Knapsack from disneydirect.com awhile ago but I don't think they have them online anymore. It was black with mickey on the front. It is a backpack, but I also attached straps incase I didn't want to put it on my back.

You can also try ebay. They always have backpacks...