I don’t think the value especially of the antidote is too overly price, Herbalism wasn’t a common knowledge skill thus is why Jerry didn’t make his own antidote and couldn’t afford one either.
during this time period you weren’t given anesthesia unless you had the money to pay for it.
I think where the balancing needs to be made is supply and demand, a shopkeeper shouldn’t accept all and any crap you sell him just because you want to sell it.
how you would go about implementing this IDK. I guess you could set it up that some merchants will buy things from you but at a depreciated value because its worth less to them v.s. another merchant.