Green living comes back as green money in my pocket

I have two salons that I frequent. A hair salon and a body salon. I could get almost everything done at one or the other, but I guess I've decided to play them off one another! My body salon is much more aggressive with their advertising and deals and things of that nature. Last month, they offered 15% a product for every hair, facial and body product empty bottle you brought in. I took in 3 and earned 45% off on products (3 products @ 15% off!). Well when they sent this month's email out they said it was so successful (15 product containers returned) they decided to do it for September too! Well, in the last week I returned 7 product containers (5 on Tuesday and 2 Saturday), so I earned a total of 105% off on products! I could make me a little killing if they keep this up...