i have 4 children and we live on a really tight budget. As far as cutting some items really look at some household things that could be cut like premium channels on cable that dont get watched very much. Try searching your current providers web sites and seeing if there is cheaper rates for things like phones and cell phones. I once lowered my phone bill by 20.00 a month just because I went to thier site and did it on the web. I recieved more services and for lower money.
I also will fill out at the walmart site for free samples, you would be amazed at how much free shampoo and the like every day items that they will send you.
As far as enternaiment, we do lots of parks and lakes in summer and pinicis. The kids 16,14,12,7 really like this. We will go to a dollar store and buy inexpensive toys to play with at the lake. You can also make obstacle course out of boxes in different sizes and come up with differnet ideas for your age in general. You can also go on nature hikes in the parks for butterflies or the like. This will also be teaching them about nature which is educational. I would suggest also looking in your local paper for free things going on in the community. I would only do one pay for activity a month if money is very tight. Buy things like toys out season is a great money saving tip. Buy winter things in the summer and and summer things in the winter for the next year. you will save at least 75% if not more sometimes.
Movies are always a good one for younger kids but this can be tricky as some young ones can sit still for that long. Make a board game from everyday items. Like for the oldest whatever his interst are research that "theme" and devise a board game with him or her. AS so on with each child.
WE also have family game night as far as we bring the video game system in the living room and we all take turns playing, you can find some really good educational games that will teach and be fun. put on a show for family and friends as a get together this is something that can be dragged out over time and have "practices" , buy the items from local good will store or yard sales.
It is always good to teach children that they have a imaganition and let them run wild with it especially at the age under 10.
As far as groceries clip coupons, and buy in bulk.
hope some of these helped wish you the best