If you had a really good time and you want to, you can get drinks or dinner or tip. Outside of the US and Canada tipping is more individual, I think. People do it when they were very happy with you service and have money to spare.Taking a DM class now and was curious if it is customary to tip your instructor, and how much? Class is in Cozumel.
If your instructor is Merican and the shop is run by Merican, I don't know what the expectation is... Europeans won't expect to get tipped usually, but they will take the extra money and won't say no to free beer.