Originally Posted by
Hirtius
I'm sure you've heard of Aldrete's book on the Linothorax. The RomanArmyTalk folk hate it since the reconstructions are glued linen, more on that in a minute. I know you aren't a fan of glued linen due to lack of evidence. But more importantly he discusses the evidence for linen armor and why the spolas likely isn't armor.
In it he discusses the spolas, which as you said is pretty ambiguous with Xenophon. It's said that the men (I think cavalrymen) were equipped with spolas and thorakes, but it wasn't clear if they were wearing both at the same time or if they were two separate types. I'm not sure, but isn't thorakes just the general term for body armor? If that's the case, it would be weird for the spolas to be separate if it were indeed armor. If I recall, the second mention is an arrow piercing a soldier's shield and spolas. This makes it sound like armor, but isn't definitive. The association with a spolas with leather armor is Julius Pollux's Omnasticon. This is dubious as an only source in many different ways, but notably how he also mentioned Sophocles description of Libyans wearing a spolas, which is a leopard skin. This rather confusing, because the two usages in the same definition seem to contradict. However, Aldrete also references Aristophanes play The Bird in which a citizen commands an attendant to give an impoverished poet their spolas. In this usage, it obviously isn't armor. It's likely that he was confused since he wrote in the second century, and Alderete believes it's also possible that he might have based it off of some leather garment worn under armor during his time which might have been referred to as such. Either way, the identification of armor Aldrete refers to as Type 4 as leather armor is extremely shifty.
Linen armor does not have the same ambiguity. Aldrete wrote a number of pages referencing the use of linen armor by many different groups.
I don't think it's possible to know how expensive linen was, but Aldrete points out that linen doesn't mean high quality luxury fabric. If I had to guess, I would say that the luxury is more recent perception. Linen was probably an everyday fabric for people then. There could have been high quality linen, but also low quality linen. Most of the cost of linen armor would have been in labor, as it requires a lot of it. But that also doesn't mean it would be less expensive than metal armor, as metal armor had labor costs of its own as well as scarcity. You mention comparison to iron armors, but during the greatest usage of linen armor, iron armor wasn't around or was fairly rare.
I did say I'd get back to the glued (laminated) linen. Aldrete points out that a 14 layered piece of linen from Mycenae has been found. The folks at RomanArmyTalk argue that it's too old and wouldn't apply to more recent time period we are looking at, but that's pretty solid evidence that laminated linen was used. There's also a laminated fragment from Tarquinia. Especially with the reconstruction, lamination is a good candidate. That's not to say all linen armor was laminated. I'm not sure if the shin guard from Dura Europos was laminated.
As is a theme in this thread, I can't give you the answer to what you're looking for. I don't know if records of availability and expense of linen from the time exist. It doesn't seem like something that would be preserved, but it would be cool if something was found.