Answer:
$300
Step-by-step explanation:
Consumer surplus refers to the gain a customer has when the price of a product is lower than what they are willing to pay. According to this, the consumer surplus would be:
Price the customer was willing to pay: $500
Price paid: $200
$500-$200=$300
According to this, your roommate enjoyed from the iPod a consumer surplus of $300 because she was willing to pay $500 and she paid $200.