I always love seeing the different responses..... Do you have the right answer?

70 worth of goods and 30 in cash

$100

in the form of $30 and the goods worth &70

100$

100$

They still made money, the mark up is insane.

Ow! my brain can't! Give me my $100 back!

$100 I say. It doesn't matter if he used "that" bill to buy something from the store. Money is fungible. If he had pulled a different $100 out of his pocket to make the purchase, no one would think it relevant.

$130
The store never made the $70 he would have spent of his own money.

Eighty bajillion dollars

$100. $70 worth of goods and $30 change.

Impossible to calculate without knowing the base price of the goods he bought and the percentage of markup on the $70 worth of goods.

130

$100

200$

$65

$170

Mathematically $100.

In RL terms , about $30 + $21 , as stock is marked up generally around 300%, therefore roughly $51 .