Like most of the stores I shop at when I check out I use the key fob (or if I forget it usually is encoded based on my phone number) with my store ID in order to get a discount. The one that comes in most handy is Binny's (sadly enough). Recently I received a package which must have been based on my purchases at Jewel - it was a packet of "gourmet" instant coffee. I assume that this is based on the fact that I purchase the Starbucks "Via" instant coffee and they checked my sales records and figured that if I tried their product (which they sent to me for free) then maybe I'd switch to it, especially since it is far cheaper than the Starbucks instant coffee.
Generally I get coupons to try new products attached to the 10 foot long receipt that they give you when you check out but since that is never around the next time I am shopping for groceries this is probably a smarter approach.