While PennDOT will publish the necessary forms to transfer titles/tags, they won't accept them if you just fill them out and mail them in. When my mother transferred the title of her car from my fathers name to hers, we mailed in the necessary forms (notarized and everything), because my father had passed away, there was no cost from the state involved, but they pretty much told us we had to go through an authorized tag agent, and their fee was about $100