When Money Grows on Trees

I've praised J.K. Rowling's through world-building in the Harry Potter series before: her setting is remarkably detailed, with an impressive amount of backstory. The one thing that always bugged me, however, was the matter of economics. Since we've seen people transfigure random trash into household objects, magically mend shattered glasses, and manifest pasta sauce, there seems to be an extremely limited market for goods and services. There are niche craftspeople, certainly, but most of these are the stuff of infrequent purchases, so what is running the day-to-day economy? And furthermore, what value is gold when you can manifest tea cups out of the contents of your rat traps and tea out of thin air?

The problem of suspect economics isn't unique to the Potterverse by a long shot. Rowling at least gives us a banking system, a regulatory agency, and some credible specialist businesses. Many fantasy worlds seem to run on a completely nonsensical economic system. This is particularly prominent in worlds where magic users can basically manifest stuff for free (see my pet peeve about magic having no consequences). If the economic system of your world is blatantly unworkable, it undermines suspension of disbelief.

The economy doesn't have to be described in great detail, nor do you need to dive deep into competing economic theories. Your fictional economy just has to be credible. Humans have used all kinds of economic systems over time, to varying degrees of success, so there are plenty of plausible examples to borrow from when you create your world. Since you're looking for conflict, the economy doesn't necessarily have to be in good shape-- perhaps there's economic stagnation, or there's been a recession, or there's massive wealth inequality. But some key things to work out:

What are staple goods in your society?How are those goods produced? Who produces them?Are there any high-demand goods that are driving an industry boom? If so, what are they?What goods (if any) does your society import and export? If so, how do these goods travel?Does your society use currency?What are the skilled goods and services in your society?Is there wealth inequality? Or is your society collectivist? If there is wealth inequality, how did it happen and how is it maintained?What are the status symbols and luxury goods, if any, in your society?
The answers to these questions can be fertile ground for creating a plot form your setting, or a rich source of complications for your existing plot. At the very least, you'll have created a more completely developed world for your audience to enjoy.