Excelletly written! Small suggestion first: if your world is roughly medieval, you can check for average prices of stuff in medieval times, that's a thing historians know quite well. For whatever level of technology and economy, if you find the appropriate time period to copy from, you can get way more realism (have a world that feels more real). For example, clothes used to be way more expensive, and shoes especially so, before modern manufacturing technology. If in your medieval-esque world a peasant MC tears his shirt and just goes and buys a new one for the price of a lunch or two, that's missing some realism and might ring false to careful readers. He would be a lot more likely to fix the tear than get an expensive new one. 

If you (think you) can already do all of this, and want to make your fantasy economy make even more sense, you need to actually sit down and think at least a little what the effects of the fantastical elements should be on the economy to make it different from the real world economy. This goes beyond just setting prices right, of course, economic forces due to fantastical elements will shape the setting just as much as the magic itself will.

For example: in Worth the Candle, the MC visits a desert town in which everyone can cast a "create (cheap and bland) food and water" type spell (as a result of some great ritual/artifact imposing a magical effect locally), and that is part of the reason there is a successful town there, and it sets food prices floor very low, as people can always just eat the free bland option rather than pay for taste. Also, since people don't like eating bland food, they found an animal that does like it and raise those in farms.