When a Mage is crafting a magical item and wishes to purchase monster parts for components (say, hearts of 4 hill giants [600xp/gp each]), does that just use the normal Equipment Availability tables, or does that follow a different standard?
If I’m trying to buy a hill giant’s heart (600gp), would it be 25% chance of one in a Class IV market?
Yeah, I’d prefer not to treat them as goods, but I can see how they might. But, I was also wondering if they might fall into another category altogether, like magical items?
The system will work however you'd like to structure it: Equipment, magic items, or trade goods. Your choice will just set the level of availability of parts.
In my own campaigns, I don't really have esoteric monster parts for sales at all. The adventurers end up gathering the parts of the creatures they kill for later use.
Considering what weird animal parts you can buy in asian citys in our world I think its not too far fetched to find bottled snake heads of a gorgon for sale in the citys of a fantasy campaign.