By resources I mean everything other than gold.

If you play with sparse resources and you don't have any metal, why should you be able to deck your sovereign/champions out in mail/plate from your own shop with only the tech.

I'm a little surprised that the shop doesn't have an 'exchange' where the merchant is willing to change whatever resource you have into another at some 'fair' ratio (fair for the merchatn......not for you).

This way, if you needed metal, but didn't have it, you could convert crystal for your purchase....but maybe at a 3:1 ratio or something like that...

That idea has been up before, but it will remove trading with the other factions.

What makes trading with the other factions interesting is that if you give some faction 1 trillion iron because you need crystals, you will see him start fielding fully armoured units. (So there is repercussions to you trading randomly). IMO this makes an exciting flow for trading.

Not saying its perfect for everyone, but still interesting
Iron will never leave until used, same with crystal, if you trade it to other items someone else will hold the iron now, to use it.

Sincerely
~ Kongdej

But isn't that like saying that if I go to buy a shirt in a store in RL I need to fork over the money and also give them the wool and yarn?

The whole purpose of a store is to be able to buy things which are unavailable to make given your resources - think of it as a trader, and money is the barter price for the materials and effort put into the construction of said item...

 But If I never had any metal, where did the shop in my city get the metal to make all those armor and weapons I have researched? And if they trade with other sovereign's cities why do they only have the weapons I have researched if the other sovereign have researched even more than I in weapons and therefore have a greater variety of them?

You have a good point about the item tech! The shop should offer items of the highest researched level among all players and charge a premium for those which you don't have the tech to manufacture yourself. This would expand on the idea that the shop owners were doing all the trading behind the scenes and offering you the items at a marked up gold cost. Perhaps there could be a blacksmith tab where you could buy items with the required resources instead of gold, but limiting you to crafting only those items you've researched.

As keli2 pointed out, I don't believe having the shop charge raw materials makes any kind of sense.

That's silly. The difference is that you need a sufficient amount of resources to fit armies with armor and weapons, however, to fit one person with armor and weapons is not difficult. Merchants can easily find ways to get supplies from other merchants, towns, countries, etc in order to create a few pieces of armor or weapons or the weapons and armor are created by blacksmiths (from who knows where) and you can purchase them. That is the difference. It is common sense.

I too would like to see a way to convert goods (metal. crystals and horses) in armor and equipment for my champions.  However I don't want to be limited if I don't have the goods (ie still able to buy for an inflated price).

I would also like to have the ability to buy goods.  The merchants of the world (collectively know as the shop) should target 10% of the worlds resources to buy.  If one faction sells 100 metal to the shop then that 100 metal should appear in the shops around the world at inflated prices of-course.  The shop should not just create the goods though, it should come from previous sell by other factions.