How about if 'suggested' pledge is $100, but you don't make them pledge any specific amount.
Here's the deal -- just getting a person's pledge into the database of the revolution is of value in itself.
You don't want to discourage people from pledging, just because they can't give, say $100. At the same time, you don't want to make a specific pledge amount of $25, because that can decrease the amount of money people will give.
If you can do a multi-amount form, from around $10, up to $2,400 -- that might work best. But, in the absence of that -- the site should saying we're trying to get x contributions of y amount -- but to please pledge if you can give anything at all.
Just my thought.