The Daily Astorian newspaper reports the waitress contacted police Friday after a couple included the envelope while paying for their drinks.
Police said they found more of the drug when searching Manley's purse and the couple's motel and vehicle.
The newspaper reports the two were taken to the Clatsop County Jail. Bensen was charged with meth possession and manufacture of meth. Manley faces the same charges as well as delivery of meth.
All seized evidence has been forwarded to the state crime lab for analysis.