Those working at marketing department at Victoria's Secret know what they are doing. Every six weeks or so, I get a free coupon for a panty (no purchase) in the mail. Often I get two, for whatever reason. After having the baby I needed to restock. So this has been great. Their normal cost is $7.50 a pair or five for $25. I know I've gotten more than five in the last few months.
Why pay for something if you can get it free? Get on their mailing list so you can receive the free promos as well. Be warned if you do go in the story you may end up purchasing something. And it can be pricey. They do have surveys that print on the receipt for $10 off $50 purchase. And the semi-annual sales in January and June are a good time to shop, also.