If the camp you are interested in has an early registration discount, take advantage of that to instantly stretch your dollars. Some camps offer subsidies to families in financial need. Camping association websites and some camp websites list information about subsidy programs. Community, church and charitable organizations such as the Kiwanis Club help send children to camp.
To find camps that offer financial aid or discounts, use the aummer camp search and check off the "financial aid" checkbox in the advanced search box Please note that many camps will work with you and offer aid to families in need, so be sure to ask the camps that you are interested in.
More information on financial aid from ourkids.net and paying for camp from camps.ca
Some organizations that help to pay camp fees:
One of the best programmes I have heard of lately is called OneHappy Camper.org. They will provide a subsidy of up to $1000 per camper who will attend one of the Jewish camps listed on their site. This grant is available for families in Canada and the US.