Wiki Voyage quotes it around 1200 TBH:
Phi Phi officially has no motorised transport, though there are a few
motorcycles with sidecars, usually used for goods and construction
material transport. Transport on land is by foot or bicycle, but in
the populated areas of Ton Sai, nowhere is more than about a ten
minutes walk from anywhere else. Longtail boats sail between all
beaches. On Phi Phi Don, you can also walk to any beach. From Ton Sai
to Long Beach, expect to pay 40 baht/person in the afternoon, at least
80 baht at night. To have a complete boat to yourself, expect to pay
at least 100 baht.
Wheelbarrows are used to transport goods, including your luggage if
you like. Expect free transport from the pier to your room, but not
necessarily in the opposite direction.
The most common ways to get around on Ko Phi Phi are by foot and by
longtail. As with most everything in an area like this, the price for
longtail boats is a negotiation. Hint: Take some foam earplugs for the
longtail boat rides. It's a fun ride but the engines are loud and
after 45 minutes it can get to you. Negotiating for longtail boats is
usually done according to where you want to go and how many hours you
want the trip to last. As an example, 1,200 baht for a 6-hour outing
to Ko Phi Phi Leh and Ton Sai Bay from the Holiday Inn Resort.
I used this website a few times to have an idea of the different prices while I was in Thailand and it was pretty accurate.
While I was there I paid a bit more around 1300 TBH.
But as Gagravarr said the prices can differ if you look and/or speak Thai.
I hope it helped you and have a good trip!