Even though i had "inherited" a couple of pairs of panties from several old GFs, my first real purchases were through the mail. I was living alone in an apartment and I had just recently gotten a Macy's charge card. I made several modest purchases of guy stuff and then when the bill came, there were enclosed, advertisements for Pam panties. Briefs and hipsters both white and pastels. I don't remember the price, but I checked off six pairs. a mix of styles and colors and both size 6 and size 7. Sent the bill away and about a week later, a little brown box came in the mail. Voila! six pair of lovely nlyon and lace panties! I could not get that box opened fast enough. I was way skinny then and even the size 6 were a little large - so I just doubled up. I put them on , rode around in the car with them under my jeans after work, very nervously went to the supermarket imagining that everyone had xray vision and could tell that I was wearing panties under my jeans. It was heaven.
Long gone from one of my may purges though. But there have been plenty more purchases since.