- “It's like when you're a kid, the first time they tell you that the world's turning and you just can't quite believe it 'cause everything looks like it's standing still. I can feel it, that's who I am” -
It's something like 2.55 bars per 3 bar item with forge and wasteless smithing.. So whatever you plan to alch/sell them for - 2.55*rune bar price would be the cost per item
Crystal hammer depends on how it applies the bars it saves.. It lasts for 28 bars saved, but doesn't appear to work independent from wasteless smithing, just doubles the chance for wasteless smithing to occur. Which means on average, wasteless smithing is saving 14 (half) and the hammer is saving 14 (half).. So if bars are 14,286 each, the hammer will break even on cost. More expensive bars you'd save a tiny amount of GP, and less you'd lose a tiny amount of GP.
If the hammer saves 28 bars independently of wasteless smithing (which it doesn't seem to) it would definitely be worth using, though.