I think it doesn't matter how much one gives per se, as long as you give from your heart.
To a rich man, $1 is nothing but to a school student on an allowance, $1 might be 10% or more of his daily allowance. There's a passage in the Bible illustrating this concept - how much is not important, it's HOW you give - willingly and with a loving heart?
Besides, charity should not be an avenue for boasting so why declare how much you gave? What's the purpose in that? Charity should be a gift with a low-profile.