That depends on how much you and your kids eat and weather your going to go for character meals, some nice restaurants or counter service. Our last trip there was DH and I (who normally don't eat a whole lot, but DH likes a NICE meal) and DS 14 ( who is always hungry).
We went to some nice breakfasts, usually counter service lunch, and then nice dinners. Diner included Palios, Le Cellier, Alfredos, Wolfgang Pucks, Liberty Tree Tavern, Yachtsman Steakhouse, etc... we went all out for dinners. Usually those sit-down meals came between $100 and $150.(we didn't drink any alcohol) Sitdown breakfasts usually ranged from $50 - $60. And Lunch at counterservice was usually around $30 - $35. We spent well over $1500 on food for 10 nights. We were planning on $250 a day for food and Souviners, and we came under that by a little bit!
DS and DH also got a lot of snacks (I had my share too) Ice creams everyday, popcorn, candy at the candy store,corndogs etc..it seemed like the more we ate the more hungry we got LOL.
We didn't buy a whole lot of things to take home, we have so much Disney stuff. We just bought T-Shirts, Sweatpants, Shorts, Mugs etc. So that didn't come to as much as some people would spend.
We also played a lot of mini golf at the 4 mini courses they have there, I think we played 8 nights out of our 10 night stay, so that can add up too.
Have Fun!