A Riddle

I could talk about school..
I could talk about my recent move...
But rather I prefer to discuss a riddle.


Three guys go to a store to make a purchase that should come to $25. However, the clerk at the store wants to make money off them so he charges them $30 with the intent of pocketing the $5 at the end of the shift. However, his boss realizes he overcharged them and tells him to return the $5.
On the way to do so - the clerk decides he'll give each of them $1 back and pocket the remaining two for himself....
So now the three guys instead of paying $10 each pay $9 each... and the clerk pockets the $2.
But if you think about that.... 9x3 = 27 + 2 = 29 ... not 30...

So where did the other dollar go?

(My labmate was asked this question and she then posed it to me - we randomly both came up with the same immediate response.... taxes! hahahaha).