I don’t know. Once you differentiate between “prostitute” and “crackwhore,” it’s simply a questiuon of plugging in other commodities instead of “crack.” Even if the Agricultural Revolution may have given us “Barleywhores,” I would say that you can’t have prostitution without a neutral means of exchange. No money, no prostitutes.
I think it’s a stretch to call a person who lives by trading sex for food with one other person a prostitute.
At one end of the range you have “spouse” and at the other you have “prostitute” but you can think of an almost continuous gradations between those things.
This debate needs a definition of “prostitute” to advance beyond where it is.
The world’s oldest profession is midwifery. (I am reliably informed by a midwife whose opinion I trust.) What comes second, I have no idea.