I was out with Jr. once and he found like a $5 on the floor and he was THRILLED. I didn't have the heart to tell my shortie to turn it in to customer service or whatever.
Once when I was a kid (living with my single mother who work min. Wage jobs, so pretty poor) I found 20 bucks on the playground. I was overjoyed. As I was walking home with a big grin on my face I ran into some other kid who asked me why I was so happy. I told him this'd found 20 bucks and he said "oh that was mine"
And I was stupid and believed him, though in retrospect, he was totally lying.