I hired a boat for the day in Nyaungshwe I paid 7000 Kyat for and 11 hour day on the water. Which is around US$8.00 That included a side trip to Indein also. That price is for the whole boat so if you meet up with people that have the same interests you could share the boat. A boat can carry 5-7 passengers.
Most people seemed to show up in Nampan by boat although I did see a couple of trucks located in the back of the market.