For the next person to try this, here are some numbers:
It takes 40gp to cure a deer hide (unless you can craft your own salt and/or tanning acid[?]). Rat or bat hides would be cheaper to cure, but I don't know where to find rats or bats (apparently, there isn't enough hide left of the sewer rats after they've been splatted).
Out of ten hides, I successfully cured one (though I did get some crafting xp for that, so maybe next time I will have a better chance[?]) (400gp).
From each deer hide (may be different for other hides) you get five "A Small Bit Of Cured Hide" (that would have cost 5x91=495gp).
So, technically I'm ahead, but there is the "Crafter - Badge of Certification" to pay off (500gp).
I can see why the halfling crafting merchant wears a mask.
So, is Mage Armor worth all this? *shrugs* 80gp a pop for a first level spell seems a trifle rich, but who knows, perhaps it that will improve. Esckew Materials anyone.