Has Low's Hierarchy of Coupons

Unlike humans, all coupons are not created equal. Some are great and some are awful. I get a fair number of coupons in the mail and I've begun to see themes. Therefore, I present, to you the hierarchy of coupons:
1. Coupons for Free Things
These are self-explanatory, a coupon that lets you walk into a store and get something for free. No strings attached. Starbucks had a promotion where, on Earth Day, you could walk in and get free coffee if you had a travel mug. I don't know why I led with Starbucks and not McDonalds, which was also giving out free coffee, as McDonalds apperently has better coffee than Starbucks.
2. Coupons that give a good discount
Okay, you still have to buy something but they provide a tangible reward. I got some Quiznos® coupons in the mail, which included a $2 off coupon. That means a sub is a third cheaper. As I may I have mentioned before, I won a bunch of Quiznos® gift certificates and so it was a no-brainer to go to my local Quiznos® and use up some of these coupons (Quiznos®: It’s the sub sandwich your mouth always wanted!)

3. Coupons where you buy something and get something else free
The pinnacle of this is the "buy one get one free" though it does have its bratty little brother that gives you a couple of free, say, couple of mints. But let's stick to the high-end of the spectrum. Why do I rank it below #2? Let's use the example of Quiznos® coupons. They had a coupon for a free bag of chips and a free drink with the purchase of any sandwich and another that gave a free small sandwich (equal or lesser value) with the purchase of a sandwich and drinks. Both these examples are worth more in absolute terms than the #2 $2 off one, so why do they value it less? Answer, I don't want chips or a surgery soda. Even something that I do want, like a sandwich, I don't really need. The generalization of this is while I can always enjoy getting something I want cheaper, getting other things cheaper or free requires me to want them. And chances are, I won't (This is why we learned in economics that cash transfers were better than food stamps).
4. Terrible Coupons
You know the kind. Buy more of something to get something you don't want. Or buy a bunch of things to get a discount off something else. There are so many different kinds of terrible coupons and, truth to be told, they make up the majority of coupons.

Now, of course, these categories are not completely rigid. A big enough discount for something I like (#2) beats something I only somewhat like (#1), though its gotta be a big enough discount to beat the FREE! Effect. Likewise, the Marble Slab coupon for a buy one get one free cone of ice cream (#3) appeals to me more than their $1 off (#2) ones (because I don't see myself ever buying ice cream by myself). I can't really think of a case where a #4 coupon would beat a #1-3 one but that's because of the tautology inherent in its construction.