text based personal assistance based in NYC

magic / go butler clone?
Not a ton of info on the website. Says $10 to join, plus 15% charge on anything out of pocket for the assistant. I'm guessing there's some rate to pay the people doing the work though? Is it by the hour? or mile? If I need an assistant to go grab a set of keys from my sister across town and bring them to me, how do I know what the fee will be?