Help me solve this.. Simple math? Stupidity?

I got this as a text message. Never really got to figure it out. Im not sure whether this is a trick question or whether its just something stupid but here is it anyway…

Say you saw a nice item for sale at $97 and you don’t have the money.
You go to mom and borrow $50. Another $50 from dad.
You go buy the item.
You receive $3 as change.
You pay mom and dad $1 each in advance and keep the other $1 dollar for yourself.
You now owe mom and dad $49 dollars each.

$49 + $49 = $98
$98 + $1 (you kept) = $99

What happened to the other $1 to make it a hundred?