Verb conjugation of "despilfarrar" in Spanish

Writing autobiography in another language has some advantanges. You do not have to think to much about the story and you can concentrate on the foreign language. Spanish is very suitable for that.
After placing my luggage there I decided to walk into town and rent a bike. The neighbor of the guest house stopped me on the street and asked me if I was Mike. She told me that she was Luisa.
Usually I do not care too much about not getting change, but when you pay a 3 dollar ride with 50 dollars, you do actually expect change. We stood there for a while and neither of us knew what to do.