Yep. In general, two combined deals/coupons aren’t allowed.
Oh, did we get BITCHED at for that!
Well, i don’t usually comment on people’s weight, but if you’re large enough to serve as a large retail store you might want to cut down on the chips and ice cream. 
I read fine print, and if there isn’t anything mentioned about not combining coupons or special offers, then I can do that. I would point that out to said employee on both the coupon and the sign. If I didn’t get what I wanted, I would ask for the manager, point out the same thing to him/her. If it is policy, it should be written. Especially anything with combining offers–most coupons have it written on them because its a pretty standard thing. But if they don’t show me the policy in writing, it doesn’t exist.
I usually write a letter. However, this hasn’t been very effective the last two times.
I always try to differentiate the person from the policy. I was once in a customer service position working for a company with strict policies. I thought they were bad policies, but it was my job to communicate them. I worried that if I said “I don’t like the policy either” (as I was so often tempted to do) the clients would use that as a way to bolster the complaint (“Even your own staff think this rule is dumb!”) to management and I’d get fired–from a job I really needed. So I ended up seeming like an ass to people. I hated that.
I try to be clear about what I am upset about in the letter.
Similarly, I try to write nice letters when I’ve had outstanding service.
Yes, mhendo, proofreading is a good thing isn’t it. For those unable to read my mind (and insist on reading my words) that should read, “As a former Wal-Mart employee…” D’oh!