What does God want from me? The first thing He wants is your heart. If He has your heart, then everything else is easy by comparison. Giving is a tangible way to express your heart to God. Just as you would give a gift to a loved one to express your love and friendship, so it is with the Lord. Giving is also an expression of worship throughout the Bible. Jesus tells us that God is looking for those who would "worship Him in Spirt and in truth." In other words, our actions should reflect where our heart is. If you are so led to give, thank you. If it is out of obligation or guilt, hang on to it until you are ready. Be a cheerful giver. (2 Corinthians 9)
If you already have a Google Checkout account you are in good shape. If not, you can create one but it isn't required for the donation. Google charges $0.20 per transaction and 2% of the total donation.