You were at Weasleys' Wizard Wheezes. It was a new shop in Diagon Alley and it was very popular. It was hard to move inside of the shop because of all the kids running about the place.

After you found some fun stuff you wanted, you went up to the counter to pay. Fred Weasley was running the counter today, he was nice but a little smug. He told you the price and you dug into your bag, your face went pale.. you forgot your wallet!

"Five Galleons." Fred said as he watched you search.