Stephanie Nelson, "Good Morning America's" Savings Mom, has several tips on how to help charities even if you're on a budget.
Use coupons. Take coupons from your Sunday paper and use them to buy items for a local food pantry.
Set up a charity sales table. This is a great way to gather specific food items to benefit a specific charity quickly. Basically, it's a food drive in a grocery store. Make arrangements with a store, get a table, fill the table with items that the charity needs, and ask shoppers to buy them.
Organize a change collection. This is the easiest type of fundraising to do -- just ask people to bring in their loose change. The best place to do this is at a school or place of worship. Also, you might want to start a change jar for your own family that you will donate every time it gets full.
Start your own food drive. Talk to a charity and find out exactly what they need (i.e. soup, peanut butter, etc.). Then, make out a flyer listing these items, and attach those flyers to grocery bags. Distribute the grocery bags to your friends and neighbors. Explain the drive and why you are collecting. Tell them you will be back in one week to pick up the filled bag.