Your neighbor is running a 5K for a worthwhile charity and hopes you’ll sponsor her. A nonprofit agency to which you’ve donated in the past keeps contacting you about additional gifts. A coworker is collecting funds to buy a milk-producing goat for a needy family across the globe.

These are all good causes, but donation requests that come one after the other can really put a strain on your budget. After a while, you have to say no to someone, so what do you do when you can’t afford to donate any more cash?

The following money management tips will help you give to charities without breaking the bank.

Develop your own donation policy. This works particularly well for friends who repeatedly ask for sponsorships. Decide in advance on some personal guidelines for charitable gifts, and mention them when a friend asks for help a second time in one year.

For instance, your standard response might be, “I only donate to one organization or program per friend, per year.” Or you might get selective about causes, saying, “I only donate to programs that benefit children (or cancer, or whatever is close to your heart).” And remember that it’s always OK to say “no”—with or without a reason. A simple statement of fact—without lots of explanation—is just fine: “I love what you’re doing, but I just can’t make a donation right now.”

Set money limits. Our daughters (who are often our most persistent donation-requestors) know that we have a set amount we’ll donate per year to each kid’s projects. I just ask my daughter, “Do you want me to sponsor you for your school jog-a-thon or the cancer walk—or a little for both? Here’s how much I’ve got to spend.”

You can do something similar for folks outside the family, too. Decide up front how much you’re willing to give annually to special donation requests, and earmark the amount for that reason just as you would for gifts or car repairs. As friends, neighbors, or colleagues ask for pledges or donations, give until your special donation category is depleted. When it’s gone, you’re done for the year.

Develop tiered giving. You can’t always donate to everyone’s causes equally. In that case, consider a tiered approach. Perhaps give a standard $25 to extended family members (nieces, nephews, sisters-in law, and so on) and close friends, but only give $10 to neighbors’ kids, work colleagues, and acquaintances.

Acknowledge that your bigger giving priorities may change. Maybe you sent a generous check to a particular health advocacy organization after your elderly parent died of that ailment. Now you’re on all of its mailing lists and get regular phone calls asking for more money. Do the charity a favor and be honest: When you receive a call, tell the representative that your donation priorities have changed and that while you appreciate the charity’s work, you’d like it to take you off its calling and mailing lists. This is a good thing: You’re saving the nonprofit the unnecessary expense of contacting a nonviable donor.

It can be hard to turn down a request for a donation to a worthy cause, but remember that you can only give so much. If you have strong feelings about an organization but don’t have the cash to spare, consider volunteering your time instead of your money.

Teri Cettina is a mom of two daughters and freelance writer who specializes in personal finance and parenting topics. She blogs at Your Family Money. Follow her on Twitter: @TeriCettina