Whenever I buy fuel, missiles or bots I do not get it at the correct ratio for example 4 fuel for 3 scrap, I get 1 fuel for
3 scrap, whatever the ratio on all of them it is always 1 item for a lot of scrap
The prices of supplies in the store are not fixed. They steadily increase in price. It's cheapest in sector 1 and most expensive in sector 7
When you get an encounter that offers some kinf of trade, the supplies offered and the price varies between encounters. Usually you get a much better price that at the store, but you never know when you will get this encounter and if it will be usefull.
EDIT - Oh i see. yeah the number on the left is the amount of fuel/missiles/drones the store has to sell. Who designed that anyway?