Unless you're going to create a functional economy and integrate the crafting into that it really won't do much other than provide an additional mini-game for people to mess around with.
First of all, all commodities, be they swords or herbs, or potions, or clothing, must have dynamic prices based on the availability of those commodities in a) the local area, and b) the world as a whole. Then every natural resource has to be weighted based on its prevalence(Locally and globally), extraction cost, and transport cost. Then you have to do roughly the same with manufactured goods, based on resource costs, production cost, labor cost, transport costs, and of course add resale markups at every link for all commodities. Then you have to simulate supply and demand and all that crap as well before you'll get an actual price out of this.
If you don't do it this way you'll end up with one or another way of accumulating wealth or goods as the most effective, hence only, way of doing it. Either looting, purchasing from shops, or crafting your own stuff will be superior, and everything else will just have been wasted time for you guys.