http://www.johnmccain.com/
That is not the same link that was given to sign the petition. This is the link, and you do have to donate to sign it:
http://www.ipetitions.com/petition/Federal-Elections-Commssion/index.html
I signed it and didn’t donate. I just hit the back button and looked at the signature tab at the top. I was signature 65x.
I know that’s not the link. I followed the link for the petition and I signed it without donating anything. It only ask you to donate it doesn’t force you to donate to sign the petition.