I had mailed in cards to Victoria's Secret 4 times earlier this year for the "no purchase required" part of one of their promotions, figuring for the price of 8 stamps I could get 4 new pairs of underwear (because holy crap, their underwear is expensive, but I DO like it better than the stuff I normally get from Target). Well, one of the cards I got back was a surprise $50, instead of the standard $10.
So for $8 I got 10 pairs of underwear for me (10 of the 5 for $27.50), which is about half the price I pay for packs at Target; and then I got 3 pairs that I'm sending to my sister for free (because they came out to $9.18 each, and the GC was for $10.)- I could have just had 13 pairs, but I don't need that many!
To do this I had to go into VS, make a purchase, leave, do a lap around the mall, come back and make another.
Yes, they were really enforcing the "1 per customer per visit" rule. So I visited 4 times in the span of a half hour. I didn't have the guts to walk out and turn around and come back in...
I also got 2 new t-shirts at JCP that I really needed to replace old ones for $2; a carefully used "Spend $10, get a $10 discount"- scoured the store for something closest to $10. T-shirt was $12, but had a buy one, get one for a penny sale :)