I don't think there is any rules against cash on pickup on eBay (AFAIK)..

Unfortunately due to many dishonest people collecting items (in person), paying by paypal only to return home with item in hand then file a dispute claiming item not sent (theft, obtain financial advantage by deception etc)...

I will ONLY accept cash on pickup....If its interstate, we have most corners covered with members on here, so cash to them, cash to seller should be an easy fix.