How do i get yo sanya island from wuhan (wuchang) in the cheapest possible way ?

The cheapest way should be train. You are so fortunate that there is a direct train (Z201) from WC to Sanya. It starts at 04:31 and arrives at 07:25 (the next day). The journey takes about 27 hours to reach. Ticket price for soft sleeper is CNY966, for hard sleeper is CNY571, for hard seat is CNY330.

Direct flights between the two places are available as well. Sometimes, U can enjoy great discounts.