Why isn't it OK to talk about how you should pay attention to things like exchange rates, to know it's OK to ask for your change, to be aware of being ripped off and being taken advantage of? Where is the line drawn, between cents and dollars? Where is the line between understanding the Jamaican culture and being ripped off? Are some of the business practices such as keeping change or overcharging part of the culture? They treat each other that way? Or just the tourists?
I think what this forum is about is sharing the realities of travel to Negril and then sharing strategies for dealing with that reality.

For example, one reality is that different places charge different prices for the same item (like a red stripe). Sometimes the same place will charge a different price at a different time (like when a large group arrives). Acknowledging this truth is step one. Sharing a strategy for dealing with it is step two. Strategies mentioned so far have included 1. Do not buy at places that charge more than you feel the item is worth, or 2. ask the price before ordering. Both will get the consumer what s/he wants and both will send a message to the establishment that prices matter.

Another reality is that if you use US$ to pay for things, the exchange rate you get will vary from place to place, and you may not get US$ change back. Strategy for dealing with this reality is to use JA$, or accept that the convenience of not changing at a cambio will cost you something. Use the JA$ change for the next drink, or save it for tipping elsewhere, or whatever.

Another is that some people will not bring you small change. Strategy? Ask for the change, and wait for it if it is important to you. If you frequent the place, make it clear that you expect change every time. If you don't like the assumption that your change is a tip, by all means take your business elsewhere and feel free to tell that bartender why.

These strategies have all been shared in this and the other threads about beer prices and coffee prices and exchange rates. We all learn as we go and this board can be a sort of shortcut for new folks to learn lessons learned by others who have gone before.