Last I checked, ChristinePAC (as in O’Donnell) would allow a user to enter a 1-cent donation. I am unsure whether it would actually process such a donation; I didn’t try any further than that. But (as I suggested earlier) if it takes buck or two to process a donation, what good (if any) would a 1-cent donation do them? In fact, it seems ripe for abuse!
