Asisreo
Patron Badass
An economy is too chaotic to really simulate wholesale, but you can take whatever the regular price for items and bump them up or down by 10% to simulate fluctuations. Maybe 5% and 1% if you're afraid of predictability.Math wizzes, Excel addicts, and GMs among us: I need to create an economy for my game. I want PCs to earn a limited, variable amount of money per-adventure, and they'll spend that money on supplies, repairing gear, and buying new gear. Some gear/magic items will be expensive and require saving between (not too many) adventures. The economy's inputs and outputs are very limited.
Toying with the ideas of PCs with art skill producing valuable work between adventures, and those with crafting skill being able to repair their own gear at an advantaged rate. Also, crafting skill and negotiating skills offer a flat 10% discount to goods/services.
Is there an easy way to do this without the PCs always needing to save money (being broke) or just sitting on piles of gold?
Keep a calendar and have certain items go on sale or just be cheaper at certain times like during the goods' harvest time or when it's offseason to need them.
For the stock market, make the companies you wanted to include in the market and generate "predictions" on their stocks. This is what happens to the company if the players don't intervene. You can add major events like buyouts or changes in management to make it more exciting and to give your players agency. When they change something about the company, make a new line predicting where the company goes now on the market chart for that company.
A crude sketch to illustrate: