Salt,iron and spices are good the way they are.
Other goods: (buying price =BP, selling price= SP).
Bread: BP=15-20s, SP=30-40s (I think there could be a shortage of food in those times so yeah, trading food could be profitable)
Ale: BP= 75-100s, SP=150-180s
Hides: BP= 50-70s, SP= 100-110s
Sausages: BP=50-60s, SP= 120-140s
Dried meat: BP = 100-120s, SP=150-180s
Pottery: BP= 200-250s, SP= 350-400s (only few units of pottery can be bought at a time)
wine: BP= 200-250s, SP= 400-500s (luxury goods are worth more,right?)
Oil: BP= 200-300s, SP= 400-600s (luxury good, hard to get)
Leather works: BP= 150-250s, SP= 350-450s,
Chicken, pork, beef: BP= 100-200s, SP = 300-400s (you can't get a lot of those and food is always pricy)
Furs: BP= 300-400s, SP= 700-900sp (hard to get)
Grapes and olives: BP= 50-100s, SP= 150-200sp
Wool: BP= 100-200s, SP= 250-400s (make it hard to get)
Wool cloth: BP= 400-500s, SP= 700-1000s (I think it you can obtain it from a workshop)
Grain: BP= 30-70s, SP= 100-150s (shortage of food because of war)
These are my sugestion. I think only certain towns should use the SP due to shortage of those goods. Don't set these prices for all towns selling a certin ware and towns looking to buy it. different regions need different goods, don't they? If a war lowers the amoun of food you can get higher prices for it in these regions.a