- BOGO - Buy one, get one. This is often a great way to get amazing deals. Walgreens, for example, will accept two manufacturer's coupons (MC) if you buy two products. So if you use a BOGO coupon on the first item, then you can use another MC on the second (free) item and save even more. Even better if you can then combine it with a store coupon. Often the three coupons lead to free or for-profit deals.
- MC - Manufacturer's coupons. It's good to know what kind of coupon you are using because most stores will only accept one MC per item. If the store also offers coupons, you can combine those with the MC to get even better deals. Most coupons are MC, but if you're unsure, they'll say at the top, next to the expiration date usually.
- $#/# - For example, $1/1 or $1/3. This is a way of saying, "Save $1 when you buy one item" or "Save $1 when you buy 3 items."
- OOP - Out of Pocket. A lot of times the savings are in rebates or register rewards (RR). That means you have to pay the money out of pocket now in order to recieve the savings (which you can then use on future purchases instead of paying OOP) at the register or in the mail.
- RR - Register Rewards. Walgreens advertises items with Register Rewards. Basically, you pay the full amount of the item, but when you check out, the register will print out a Register Reward for a specific amount that you can then use on a future purchase just like cash. They do have expiration dates, so be sure you use them in time (I currently have $21 in RR that expire tomorrow! Time to plan a shopping trip!) There are some rules you have to follow, but they're pretting simple. (For example, you can't use RR to buy prescriptions or medication, nor can you use an RR to buy the same product you got the RR for.) You can read a good write-up of the RR rules here.
That's all I've got on the top of my head today, but I'll add to the list as I think of things or as people ask.