How to balance purchasing gear?

[c0matose]

I feel sometimes that buying gear is almost too easy. DF has nice rules for selling whereby you cant always sell something for the full price, but i wondered how it is possible that all blacksmiths always have all variants of weapons available for the same price.

I recently watched a Witcher III video in which Geralt spoke to the blacksmith and got the speech option "is my sword ready yet?" I assume this means that you select what weapon you want and then after a few in game days the blacksmith has made it for you.

I was wondering how I could implement this into a GURPS DF game. My idea was that a vanilla item (eg Broadsword) has a 75% chance of being available in a blacksmiths shop, modified by the population of the area because a large city would have better stocked blacksmiths than a small village. For each enhancement you take 15% off its availability, so a Dwarven Broadsword would have only 60% chance, and a fine dwarven broadsword 45%, and very fine only 30%. If it isn't available you have to order it. You have to wait a day per $1000 that it costs. A large knife or other object cheaper than $100 is available the next morning/afternoon depending on when you order it. The final price is then increased by $50 per day you wait, to pay for the craftsmans time. eg a very fine dwarven broadsword would take 12 days and then have a further 240 added to the price, adding up to 12600, or would have a 30% chance of already being in stock.

A second idea was that the price of all items simply vary by 10% either side, depending on the success of a roll, and modified by haggling.

How balanced do you guys think this is? I feel it adds more immersion and tactics to buying items, particularly "late game" when you really need specialised items, and would make the player think if they really need that Very Fine Dwarven Broadsword between now and the next city, or if they can wait and possibly save time and money.