We weren't really on a budget when we went last year, but I don't like spending money where I feel it isn't worth it. The biggest thing I can think of is don't feel like you have to eat at places in the parks. We were pretty much across the board underwhelmed with the food there, and we ate at most of the must do places.
We stayed half the trip at the Disneyland Hotel and the other half at the Courtyard by Marriott Anaheim Theme Park Entrance, which was conveniently right next to Mimi's. It saved a ton of money with both those, and it was easy walking distance.
The best bang for your buck I can think of for food would be that fried chicken place at Knott's. The waitress was great, and food was amazing. Plus the waitress literally found ways for us to save money on our completely way too much food for a normal person portions, and ended up giving a pie to go home with too... for reasons?