I hope you like junk mail.
OTOH: Toomey always sends a stamped envelope. You can cut the stamps off and use them.
I don't mean to be rude, but like you, I decide how much I have to give, then give it. When they take my first donation as a sign there may be more, it makes me grumpy.
One of the campaign's recent tricks was to mail me a $1 bill in a clear envelope so I could see the dollar. I mailed the bill back in the stamped envelope. That way they only wasted $.63 plus the original postage.
Shalom.