They'll throw in a return ferry transfer, too. (timeoutdoha.com)
Approximately a 2 - hour drive from Mombasa airport plus a short ferry transfer. (somak.com)
Similarly cheap, the picturesque journey by bus is a good option, and combination tickets that include ferry transfers cost between 800 to 1,500 THB depending on the class of bus. (whatsonsukhumvit.com)