Noob question. Let's say a provider charges 150 for HH, does anything go after that 150 is paid or does that 150 only get her in the door?

Well reviewed providers should never upsell, at least not for any services beyond walking through the door.

Legitimate providers will charge more often for greek and perhaps certain fetish type of services.

Stay with well reviewed providers and you won't have unwanted upsell situations.

But in my opinion, as a true gfe, the 150 should cover the half hour's activities.  
There may be an additional donation for greek which is pretty common, but that just gets me in the door crap is a BS rip off to me!

Sounds like you got tangled up with an upseller rip off artist.  
Sorry to hear that.  That is why you should stick with well reviewed ladies.

thx for the reply. i didn't get ripped off, i just wanted to double check and see if there were any hidden costs that i wasn't sure about.