Just returned from 10 days at the BWV and did a lot of in room cooking/eating. For 10 days we spent $400 on food for four people, that averages $40 a day for all of us. We did eat 3 large meals out (lunches which are cheaper then dinner) and ate at the fast food stops in Epcot about 4 times. To be honest, we have spent over 25 days in WDW in the past 9 months (yes terribe I know

and we really enjoyed just coming back and sitting at the table to eat this time, the $$$ saved were a real eye opener too)
We really enjoyed eating in our "home". I'm posting my grocery list to give you an idea what we ate.
5 dozen eggs - Actually they were not large ones and you really need to make about 4 per person if you were scrambling them for it to be a normal portion. We did eat a lot of eggs in the morning which is something we never do at our regular home, but if we had eaten a full breakfast out we would probably have eaten the same amount of eggs over the course of the 10 days. FYI the eggs were $1.08 for 18 eggs. So the total cost for eggs were in the $4.00 range. Granted they didn't come with characters, but I also didn't have a $60.00 breakfast bill every day either.
4 - large loaves of white bread
2 -six pack packages of English muffins
1 - 8 piece package of waffles
8 - 2 liter bottles of soda
5 gallons of water (price was 57 cents per gallon -- not $2.50 per small bottle in the parks)
4 64oz bottles of gator ade
8 sprout bottles of gator ade
2 gallons of milk (about a half of the last gallon was not used)
2 1/2 lbs of chuck chop (made about 7 nice size hamburgers)
1 lb of Turkey
1 lb of Ham
1 lb of Salami
1 lb of hot pepper cheese
1/2 lb of American cheese
1 - 8 pack of hamburger roles
1 onion (about half was left)
3 frozen pizza
1 - 20 oz box of Frosted Flakes
2 gallons of OJ
1 lb. of butter
12 Milky Way Bars (we froze them and ate them frozen)
2 gallons of ice cream
2 containers of Ready Whip Cream
1 bottle of chocolate syrup
1 bottle of ketchup (about half was left)
2 - 1 lb bags of potato chips
2 pkgs of pop corn (I did bring 4 pkgs home that were left from box)
6 plums
3 peaches
3 bananas
2 lb package of twizzlers
1 very large bottle of All Laundry detergent. About half was left, that I left a note for housekeeping to take for their own use. It was so cheap, only $3.99 that I didn't care what was left. I did about 15 loads of wash, including doing the towels that I felt I got my money's worth out of the bottle. Also for the record I came home with all clean clothes. I did laundry every night as we took off what we wore that day. It worked out great.
We spent about $150 in groceries for the 10 days. We did our food shopping in
Walmart by marker 16.