The very first purchase I ever made was a pony. I'd saved my one quarter allowance for weeks, and I must have been five or six, and I had just enough to buy Sweet Sundrop. So I carefully picked her out, she was the prettiest thing I'd ever seen, went up to the counter with my parents and... discovered sales tax.
My parents paid the sales tax, but I was addicted from there. They'd already gotten me a few at home, that's why I wanted more, but somehow getting my own was a huge thing.