The Fundraising Authority blog says You Aren't Paying Your Development Staff Enough. I'm inclined to agree (though I've known a few development staffers who were paid way too much).
You usually get what you pay for. If you're going to the bargain basement for your fundraising staff, chances are you aren't getting your money's worth:
[T]he best non-profit organizations ... realize that good fundraisers are hard to find. Mediocre fundraisers (like mediocre salespeople) are a dime a dozen. When they find a great fundraiser, they pay them what they are worth. They give them responsibility, keep them interested, engaged and happy.
Your fundraisers are the people who make everything else you do possible. They are worth paying. If you have some who aren't pulling their weight, let them go as quickly as possible and get some who are worth paying. It can make all the difference for your cause.