You would not do the hour of labor for $150 unless you felt $150 was worth MORE than one hour of your time. I would not pay $150 for that hour of labor unless I thought that hour of labor was worth MORE than $150. Both of us come out of deal thinking we got the better half. Both of us are better off afterward. Pretending this is a zero-sum game only works if you forget that in every transaction both parties think they are getting the better part of the deal.
As for your contention that it is zero-sum for the resources: If you don't take my $150, you will get $0 for an hour not spent performing this labor. And $150 in my pocket has no value until I spend it. Resources only have value when they are traded. And generally, they are only traded when both parties feel they will gain something by trading.
Where I have a problem with this is when it is applied globally. If as I say, transaction "always" benefit both parties then growth should be expected and economics should be the study of delta growth (growth acceleration?). If both parties always benefit from trade then the yardstick for the economy should based on how much more benefit I get today than I got yesterday and not the amount I benefited.