The difference between the maximum price a consumer is willing to pay for a product and the actual price the consumer pays is called

The answer is consumer's surplus

Explanation:

Consumer's surplus is the difference between what the consumer or buyer is willing to pay and the amount he or she eventually paid.

For example, Mr A is willing to pay $100 for a product and the producer is willing to sell for $90. After much negotiation between mr A and the seller, he eventually paid $85. What he paid was lower than what he was willing to pay before.

So the consumer surplus is $100 - $85 = $15