Do share some of your ideas.
-Target is awesome. It's on Harbor and is worth the few dollars worth of a cab ride or there's an ART stop across the street. Get bottled water (SERIOUSLY get bottled water! Anaheim water is gross and bottled water is expensive at the parks), juice boxes and portable snacks and even some frozen microwave foods if your hotel fridge has a small freezer. We got $5 deli trays of meat and cheese and a box of crackers and that was a nice snack at night with some substance, but would also be fairly easy to take into the park in a ziploc bag with a cold bottle of water to keep the cheese and meat cool in your backpack. We froze our water and juice boxes and they were mostly slushy by lunchtime and still cool by dinner, so I REALLY advise that! They also help keep YOU cool when carrying them
-I see from some of your other posts that you're staying offsite. If you haven't booked yet, try to find a hotel with free breakfast. Our hotel included breakfast, and almost every day I would have a PB&J out of the bread and condiment packets, which kept me full til lunch. You're going to be spending a minimum of $10 PP on breakfast if you eat out, so that saves you a bundle already. Plus, most kids want to get to the parks so trying for a sit-down meal will probably waste your money most days. Save that for your character breakfast!
-Granola bars and other stuff you might find in a school lunch for a snack will be your best friend for adults and kids alike. If everyone is getting a little hungry between meals, you could end up spending $5+ per person on something as simple as trail mix, a cookie, or a pretzel. A special treat here and there is worth the money, but it'll add up fast. A box of granola bars is much more economical and will satisfy kids just as well.
-You can always bring actual lunch in as long as it's already prepared (ie no jars of mayo). We brought in Subway (corner of Harbor and Katella) which was great. A footlong ham was $6 and fed me and my mom. If you make it a meal for something like $2.50 more, you get two cookies and a drink which is, again, easy to split.
-Check websites of restaurants to sign up for email mailing lists. Buca Di Beppo has one, for example, for a free 'small' pasta, which you can get to-go (which I highly recommend!). What that actually equated to was a massive tin-foil takeout container of pasta that fed me for at least 4 solid days, 2 meals a day! Plus they included some paper plates and a loaf of bread. You could easily feed your whole group a meal off of that one free coupon.
Other restaurants offer free starters, buy-one-get-one offers, etc. Places also occasionally offer kids eat free with paid adult meal, Denny's and iHop usually do this.
Mimi's down by Hojo offers a free 4-pack of muffins or croissants with a $5 purchase if you sign up for their email club. My mom and I got a French Dip with side soup to split and that was enough for a meal for us, and the muffins made for good snacks later. One muffin could easily be a filling snack for a kid.
-The Pizza Press is across the street from the entrance to DL a favorite of mine for good deals. There is a discount coupon usually available for it. One pizza is $10 and you can load it with whatever you want, which means you can half-and-half it. That brings your cost down to $5 per person, potentially with leftovers and everyone gets what they want. Earl of Sandwich in DTD is also fairly inexpensive, $7 per sandwich and they're large enough for younger kids to split. I'd say you get about as much as a kid's meal at Subway if you split it. If you have juice boxes in your bag, that cuts down your costs even more, so a sandwich lunch meal costs under $4 PP if the kids split a sandwich. Even if you have your own at $7, it's one of the more filling cheap meals there is in DTD. You can take the monorail from Tomorrowland to DTD and back. Splitting meals is a BIG money saver, one way or another and I highly recommend peeking at other people's plates when deciding where to eat. Rancho Del Zocalo's meals, Royal Street Veranda/Pacific Wharf bread bowls with soup, etc. are large enough portions for even adults to share.
-Counter service restaurants inside DL and DCA are your best bet for most meals. They're cheaper than table service and you can find most of the same popular foods served CS as you can TS.
-I didn't try this myself, so someone else will need to confirm, but I read a tip before I went about purchasing a double cheeseburger in the parks and asking for a second bun for a small charge. Boom, serves two. Smokejumpers Grill in DCA has an extensive toppings bar that can turn a fairly plain burger into something a lot more substantial.
That's all my brain can squeeze out for now, but I hope that helps a bit at least!
... so each of one takes about $100 per day but honestly I wont spend it all, maybe $50 if we dont drink 
