Generous woman donating money © R. Michael Stuckey, Comstock, Getty Images

When your own budget is tight, helping others is probably the last priority on your to-do list. But charities need more help than ever, because there are more people in need and because consumers tend to reduce their own giving by about 2.7% during long recessions, according to the Center on Philanthropy at Indiana University. (The average household typically gives about $2,247 a year.)

Besides, being charitable doesn't necessarily meaning forking over cash. It also includes volunteer work, blood donation and even signing up to be an organ donor.

Here are seven ways to donate to charity, without spending more money than you are giving already:

Develop a plan. Many of us give haphazardly throughout the year, donating $30 for a friend's walkathon here and $100 at a school auction there. But Lisa Endlich, the author of "Be the Change," says that's a mistake. "It doesn't make you an effective giver. You don't know how the giving is being used, and it's not something that's integral and important to you," she says. "People do their best giving when they focus on what matters to them the most."

Instead, Endlich recommends that people focus on the one or two things matter that most to them and will affect others most. Inspiration can come from almost anywhere, including movies, a conversation with friends or a magazine article. When you give to those priorities, you won't spend any more money than you already did throughout the year -- it will just be in a way that better reflects your values.

Learn everything you can about your chosen cause. Bill Gates shared this advice for would-be philanthropists: "The key thing is to pick a cause, whether it's crops or diseases or great high schools. . . . Pick one and get some more in-depth knowledge" by traveling, reading or volunteering. Studying up on your cause doesn't need to cost much money, but it will make you a more informed -- and more effective -- giver.

Give of yourself -- literally. Gretchen Rubin, the creator of the Happiness Project blog and author of a best-selling book by the same name, says signing up to be an organ donor or giving blood can boost your own mood, especially in a recession. "If you're feeling impoverished . . . a way to counteract that feeling is to do something generous," she says. It's a way of convincing yourself that you have something to give.

Give time. Volunteering at a hospital, making dinner for a sick person and working in a soup kitchen are all ways you can donate your resources, and they don't cost much. To make it more fun -- and even more affordable -- sign up with a friend.

Make sure your money is being used wisely. If you do decide to donate money, be sure it's being spent wisely. One helpful website is Charity Navigator. Just type in the name of the organization and see what pops up.

Clean out your closet. Many nonprofits and shelters are constantly looking for used books, clothes, CDs and other items. Spending a few hours cleaning out your house could result in several bags of goodies -- and you'll have a cleaner house.

Find power in numbers. Lisa Philp, the former head of philanthropic services at JPMorgan Private Bank, says women in particular often enjoy working together to fund projects. You don't necessarily give more than you would have otherwise, but you generate more leverage. Giving circles, where people pool money as a group and jointly decide where to put it, are one way to do that. Philp participates in one such group in New York that focuses on supporting projects and organizations led by Asian-American women.

"You end up learning about more organizations than you would on your own and gain from the collective knowledge of others," Philp explains.

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