I am going to join Phuket Expat Golf Society, 4100 baht and I will get discount on most courses. This only available for expats who live here. I also think you can sign up for a membercard at the driving range at Laguna, 1000 baht/year or something which also give you some discounts. This is available for everybody.
I played golf with an American guy today, he played at Mission Hills yesterday and on Wednesday, Greenfee is 3800 baht + caddy & rental fee's.
I have been playing at Phuket Country Club, the 9 hole course a lot lately and I pay 850 baht for green fee and caddy. (I use my own equipment) I really like that course and it is close to Patong. Another reason I like 9 holes is that I dont need to wake up early in the mornings, I can play in the afternoons.
I have some basic info about the courses at
www.phuket-info.com/golf.htm