This reminded me of the time when I was a kid (maybe 5 or 6 years old), I went with my aunt to buy the newspaper or something like that. They were also selling

This reminded me of the time when I was a kid (maybe 5 or 6 years old), I went with my aunt to buy the newspaper or something like that. They were also selling these scratch lottery tickets and my aunt would usually buy me one or two. I don't really remember how, but I figured out that the scratch-off paint on the winning tickets had a slightly jagged edge. My aunt couldn't beleive it, nor could the seller: she would buy me the first ticket, I'd pick it out, scratch it and use the proceeds to buy another one. This went on for a few days... After my aunt bought me the first one, I'd proceed going through the whole stack until I picked out all the winning tickets. Unfortunately, the best I could do is win back the money invested, as the most frequent prize amount was the price of the ticket.