What was HF, how long was the massage for and was it an acceptable massage..did you get what you wanted? These are the things to factor in. I know most AMP girls work primarily on tips but if the massage sucked, shorted on time, etc then dont feel obligated to break the bank on tipping for subpar service. Agree with others assuming 60 mins and massage was decent with no extras or HE about $40, $20 was too low