A.,
Instead of eating out (even at McDonalds), make up sandwiches and take them on a picnic (at a neighborhood park or other outside, free area). You can bring apples and homemade cookies, and a bottle of fruit juice and your boys will like it much more than a fast food meal.
The tip about adjusting your thermostat is a great one. I'd also add to use weatherstripping around door and window frames, even in the summer if you have airconditioning. Teach your boys to turn off lights, tv, etc. whenever they leave the room and teach them by your example. You will be saving money and also helping reduce our need for more energy. Let your sons know they help the environment when they don't waste electricity. Fix any leaky faucets or toilets you have because a slow drip can waste a lot of water over the course of a day.
Shop at thrift stores for almost anything (nonfood) you need. Salvation Army etc. have housewares, home decor items, that are so much cheaper than you can find anywhere else. Sure, you may have to search harder to find what you can use, but the money savings make it worthwhile.
Before you throw away anything, think if there is a way you can reuse it. Aluminum foil can be wiped off and reused, plastic storage bags can be washed and left to dry on tall bottles. Wash empty margarine tubs and use instead of the disposable containers. I'm sure a lot of websites have more ideas on how to save -- you might try the Mother Earth's website. I even use paper grocery bags to wrap boxes that I mail gifts to relatives who live out of town.
If you have the space, grow some vegetables and get your boys to help. It is really a great way to show them how the food they eat starts out. Too many kids today, don't have any idea of how their food gets to their plates. Fresh tomatoes in the store in my area, start out at over $1.69 a pound and go up from there. Not only do you save money when you grow your own, they taste soooo much better than what you get in a store.
I think it is great that you are trying to live frugally. I wish more people would do it -- we have become such a wasteful society. Good luck.
C. J