You have a lot of self control. If I bought such a cookie, I would eat it. Maybe I'd put a piece aside for later, but 'later' would probably be half an hour :))
Best for me not to commit to tasty, unhealthy food because I'll just eat it all, eventually.
As for the cookie sale at school. That distresses me. $5 a cookie! Maybe the kids made a profit, but that's steep for families. What happened to bake a pie, a cookie, a cake and bring it in? Then charge $2 a cookie. Profit margin probably the same and more affordable for the parents and kids.
I remember once baking a pumpkin pie from scratch for a school fundraiser. I put so many fresh ingredients in that pie it probably cost me $10 to make, even though I grew the pumpkin. The pie sold for $6 at the fair. Still, the school made a great profit and I felt really good about my participation. It was a bonding event for the school community.
I guess I'm really old fashioned.