You went to an action figure shop to buy a figure of your favorite anime character. The purchase price was $20, and the selling price was $30. You gave the shop owner $100, but the owner didn't have any change. So he went to the neighboring shop, got change for $100, and gave you $70. Unfortunately, the neighboring shop owner found out that the 100-dollar bill given to him was fake, so he went to the action figure shop and got back his change of $100. Now the question is, how much did the owner of the action figure store lose in total?