We spend probably $250-$300 average per month at the grocery store over the year for our family of 4, plus 2 cats and 1 dog.
I use a mix of things such as
www.savingstar.com and evic coupons as well as my weekly delivered Sunday paper with coupons. My MIL mails me her coupons as well weekly.
The best deals to stock up on are those that combine all of those together.
I am very selective about purchases and have created 'buy' prices for many things. I rarely ever pay full price for anything.
I stock up on lots of things when I can get a great deal on them.
Meats I purchase only at certain prices and stock up when the grocery stores hit them up. For example, 7:15am Ingles discounts their meats about to expire, and they are usually gone by 7:45. Prices are much cheaper than the current sale price. I stock up and freeze meats like that. I do know different areas of the country average different meat prices so my 'buy' price may be lower.
I also stock up on sales. Harris Teeter for example runs super doubles and triple coupon sales every few months. Combining with their regular sales, This week I've stocked up on spaghetti noodles at $0.25 per box, Special K cereal at like $0.50 per box, Free jif-to-go packs, free trail mix, Mission tortilla shells at $0.69 per pack, 100% juices for the kids at around $1 per 64 fl oz, Seattle's Best coffee at $1 per bag. Canned vegetables for under $0.50 per can.
Fruits and Veggies I stock up on at places like Aldi when they are running deals.
I occasionally shop at SAMs, but honestly, I am only interested in things I can't use coupons on elsewhere because using coupons on individual items is much cheaper than no coupons on bulk purchases at superstores.