The earliest may indeed be prior to DNA as some sort of autocatalytic mechanisms wherein several chemicals maintain an ecology to support (produce) each other.
Single cell prokaryotes have specialized chemicals which are not, however, localized in the cell.
Eukaryotic cells divide space for more efficient segregated chemistry.
Multi cell organisms have spatial differentiation for improved division of labor.
In each of the above cases the quid-pro-quo is attained as an evolutionary stage. There is as yet no quid-pro-quo between individuals. It takes millenia to make a deal. Each deal requires new chemistry.
During the Cambrian explosion separate organs developed to further specialize efficiently. Ducts were the trade routes.
Predation had already arrived but that was unilateral; not really trade.
Ecology can be considered as a form of trade when cycles of organisms arise that mutually aid each other, mainly thru their death. Such loops usually include predation; but the prey species benefits indirectly.
Symbiosis probably arose with the Eukaryotes. Predation led to surrender which led to the predator having an interest in the health of his prey. Coevolution is necessary to seal the deal.
I think that I am missing several stages here.
Animals evolve to form communities of individuals with specialized jobs. There may be no quid-pro-quo between individuals, however. Social insects specialize chemically and morphogenically, if not genetically.
It is thought that bats recognize individuals that have aided them in the past and reciprocate. The bats that do this have a much larger brain. Similarly for monkeys; grooming may be traded. This is a genetic trait that results in individual quid-pro-quo. Perhaps for the first time deals are made in days rather than millenia. New chemistry is not required for each new deal.
I suspect that instantaneous trades occurred first between members of neighboring tribes. Each had what the other wanted and neither thought it worth doing a favor for the other. Perhaps that was the first “rational quid-pro-quo”.
Money happened. See wealth.
Capitalism was then a small step. Here is what I foresee.