Mind Riddle

I have enough stress but someone challenged me with this mind riddle. PLease Please help me!!

I borrowed $50 from my mum and dad each which amounts to $100. I took this $100 to buy a pair of shoe at $97. The shop returned me $3 and I in turn gave $1 back to mum and dad each. So I am left with $1. After returning, I still owe mum and dad $49 each which add up to $98. So, $98 with the $1 I have, it totals up to only $99. Where is the another $1?