Keeps eating my cash!!!!

My son wanted to buy the purple truck, which is $470thou.
He had $142,000 cash on hand, so, I bought $400thou cash for $3.99.
But when I went to buy it, the $142thou that he already had was gone and we had only the $400thou that I bought for $3.99.
So, I then again purchased $100thou for $0.99 because we were short $70thou to buy the purple truck.
When I went back to buy the truck, I found only the $100thou cash and that the $400thou that I bought for $3.99 was missing.
What happened?
Where did my purchases go????!
Is this a scam?!?!

YGaficionado about Monster Truck Crushing Power