how much to tip

We are planning on taking taxi to maho beach, 2 adults. Taxi ride is $20 one way. How much do you tip. This would be the first time ever using a taxi and I am not sure.

I usually tip 20%. With that being said though, I never tip less than $2(even if it is a $3 ride) or more than $20. I also will never tip if I am "taken for a ride". St Martin though has fixed rates most times to most places so you don't have to worry about them cheating you.

thank you for the reply. Was just trying to figure out how much cash I need to bring.