Back in the days we sold them for 50 gold per piece.. now I have a crafter some people think 140 is a good price! For you all, 100 gold is the maximum for any sane crafter, it takes so much time to salvage and hinge these Firebrands, that anything more than 100 gold isn't worth it.
Why? It takes a good 20 minutes per Firebrand, that's a lot of time for just making app. 50 gold. Besides, Merchants offer you a way lower price than 100 gold.
The only time I pay more as 100 per Firebrand, is when I get to buy a whole stack of them (10 or more).
Most profitable though, is just putting my mana Eldy in a Fin group and level along, buying all FFB's that drop while farming money and drops :D