You'll find a big range as prices vary all over the country. Some areas also offer double and triple coupons which can really help the budget. I live in the Northeast and there are no stores in my area that offer double and/or triple coupons. I really don't use coupons much as most of the time you have to buy three of four of a brand name item to get $$ and I find the store brands are much less expensive, even with the coupon.
We're a family of 4 (DH & I, DD-17 & DS - 15). I average $130-150/wk at the grocery store. That includes all of our cleaning supplies, paper products, laundry detergent, shampoo, etc. I've found what really helps our budget is meal planning. I look at the flyers, see what's on sale and plan our meals around that. I also have a freezer and stock up on meats when on sale. A couple of weeks ago boneless skinless chicken breasts were $1.89/lb. I bought 40 lbs, brought it home, packaged into meal size packages (we have a food sealer) and froze them. I do the same thing for hamburg, pork, steak, etc. Some weeks I don't buy meat all all if nothing is on sale. I try to spend no more than $2.50/lb on meat and $3.99/lb on fish. I also try to spend no more than $1.50 on fruit. It can be a challenge at times.