I'm sure many of you have heard it before but I just can't figure it out.

So anyways...

3 guys go to a hotel that costs $25 (its a special) but the cashier rings it up as $30. So each guy pays 10 bucks. Then the manager says "you idiot we're only charging $25 a room tonight". So the cashier takes 5 one dollar bills thinking about how to split it up between the 3 men. So he gives each man back $1 and keeps $2 for the tip.

The riddle is if each man payed 10 and got a dollar back they each spent $9 correct? Where did the extra dollar go?