{(Ore Cost * amount) + (Crystal Cost * amount)} / Number of shots per craft.
Ore cost is basically a NPC price. All that matters is what taxes are in each town, and what ones are the cheapest. 312a for Soul Ore is the MAX you should have to pay. (Giran @ 15%) If Giran is maxed out, some other towns (not all) can get under that price with minimal taxes. (Gluido at 1% = 302a)
Crystal cost depend on if you are crushing NPC items or crafting your own items to crush. Thus, NPC cost is the price ceiling, while whatever you can craft/crush/buy at cheaper is your lowest value....it's just not reliable in most cases to get them that way.
If you are selling Shots, obviously you want to sell at a slight amount over NPC minimum...and then do what ever you can to get your actual costs even lower! That way your turnover is no better or worse than the pure NPC fed shots, but you make more per shot sold. And if you end up having to NPC everything due to lack of cheap crys/ore, you still make that minimum profit.
I'll say this right now though...if you haven't already done the math to figure this out yourself....you may as well not bother trying to sell shots to make money. And if you are buying, you may just want to shop around to get an idea of what your server's average price range is, then 'stock up' when you find the cheaper prices.
Otherwise, you're just asking for a vacation ticket to the World O' Hurt via Dorf Express.
dg can sometimes be measured as .5a profit per shot...
while ag can be almost 40a profit per shot
but then while .5a isn't much at 11a per thats still 22% of the total cost which is good profit
ideally you try to have
{(Ore Cost * amount) + (Crystal Cost * amount)} / Number of shots per craft.
work out to sell price / cost = 1.25 or better
cause otherwise you're wasting your time crafting
another way to get ss is to set up buy shops for a couple adena short of average price and resell for higher (less profit overall but more ss than producing it yourself)
basically it comes down to a simple math equation
cost to make + cost of time to make (ie how much out xp'ing would you make) + profit margin = sell price