Trip to the store...

So, hanging with the cousins this week (Gray family) for spring break. The middle child and the nearest cousin convince me they should go to Target to buy a video game. Now, I know my child has money for the game, but the cousin? Not really sure on the cash situation and/or their parents willingness to allow the purchase. Being the good uncle, I decide it doesn't matter what they think (I mean, I'm only here for a couple more days anyway, right?). So, I check on the cash situation...

Me: So, do you have cash for this game?
Cousin: Well, I have a $40 gift card. That should be enough and if not, I have some money so it should be fine.

Now, the "it should be fine" part frazzled me, but you know, I decided to take the chance. At the checkout, here is the story...

Checkout lady: The total will be $30.50. How would you like to pay?
Cousin: Here is a gift card. One of these has $40 on it. (hands one of two gift cards over)
Checkout lady: Well, it isn't this one. This one only has $0.14 on it. (Takes the other card). Nope, not this one either. This one has $4.00 on it. You're total is
Cousin: Hmm. Well, here's this (hands a wad of cash). It's $21.00...

(right about now I'm smacking my forehead)

Cousin: I'd have more if my uncle had let me bring the change...I had $4.00 in change...

(Checkout lady rolling her eyes at me...we've both done the math and it don't add up...needless to say, the little urchin owes me money...)