Help me with this Riddle

If Sam borrows $10 from 3 different ppl..

He buy something.
And gets $ 5 change.

He gives each person $1 & keeps $2 in his pocket.

That means he owns each person $9.
Therefore $ 9 x 3 = $ 27
And his $ 2
Then thats only $29
Where's the $1 ??