Yes. If you’re using a Hop card, you can reload using cash at hundreds of stores including Fred Meyer, Safeway and Plaid Pantry stores, and at the TriMet Ticket Office at Pioneer Courthouse Square.
You can also buy 2½-Hour Tickets or 1-Day Passes with cash on board buses and from ticket machines at MAX and WES stations. (Remember that exact fare is required on buses — drivers cannot make change.)