Abbreviations

$2/1 — Coupon value, i.e. $2 off 1 item
AC — After coupon
AR — After rebate
BOGO, B1G1, B1G1F — Buy One Get One free
CAT, Catalina — Coupons which are printed at the register. Sometimes you receive them for purchasing certain items and they are good for dollars off your next visit (see OYNO).
CPN — Coupon
DND — Do Not Double
ECB — Extra Care Bucks (CVS rewards program, prints on receipt)
ETS — Excludes Trial Size
Filler — An item or items you buy in order to get your total up to a certain amount in order to use a percentage off coupon
GM — General Mills Brand
MFG, MFR — Manufacturer
MIR — Mail-In Rebate
OOP — Out of Pocket
OOS — Out of Stock
OYNO — On Your Next Order (or to me, it makes more sense as on your next visit)
P&G — Proctor & Gamble (coupon insert in many Sunday newspapers)
RP — Red Plum (coupon insert in many Sunday newspapers, also a website)
SCR — Single Check Rebate (Rite Aid Rewards Program—must sign up online at their website, rewards are mailed to you. Different from UPR.)
SS — Smart Source (coupon insert in many Sunday newspapers, also a website)
Stacking — Using a store’s coupon with a manufacturer coupon
UPC — Universal Product Code (a.k.a. bar code)
UPR — Up Rewards (Rite Aid reward, printed on your receipt. Different from SCR.)
WYB — When You Buy
YMMV — Your Mileage May Vary (or to me it means, sometimes store policies vary so this may or may not work for you)