Western trade

Some thoughts.   When you go to the buy screen and try to buy something you can you use arrow keys. The left key increases the amount, the right key decreases it; but it should be the other away around.   This is because on the screen you see two chevron arrows and the UX is telling me that right increases it and left decreases it.

I'm confused as to how buying works. 
> I buy water at $2.  It increases in value by 1.  I buy another water at $3.   
What happened to the water I bought at $2?  Is it still $2; or is all water I purchased now $3?
This makes a huge difference say if I bought 5 units of water, that's $1 + $2 + $3 + $4 + $5; for a total of $15 spent.  But there is no way to make profit on this.  The water isn't going to $15, let alone $16.

The price difference between the cities is way too small.  One dollar difference is just a game of incrementalism.  

Therefore, the units of items you buy should hold their price until you leave the city and some time passes before the price changes.

I also think that there should not be the same items in each city.   Split things into things it supplies and things it demands.  A bit like railroad tycoon.  Some cities want mail, some provide milk.   Maybe there is a few 2x.  So a city might pay 2x for milk but it has a timer.

Maybe there is also a newspaper which has an event.  Events do not need to be negative. 

this is one of the most original TIC-80 idea for a game. Its not everyday that you see a trading sim. The core is good. now you can implement some backstory and radon events to cause price fluctuations and minor bonus/onus while you travell betwen the points!

First game eh? Not gunna lie, it was not fun. But keep it up! You should have your current amount of money show up while shopping.

Couldn't figure out how to buy anything. I think the city screen would be improved by displaying controls.