A longer excerpt, found here:
Uchicago "Montesquieu Spirit of Laws, Republican Government"
"But if the spirit of commerce unites nations, it does not in the same manner unite individuals. We see that in countries [Holland] where the people move only by the spirit of commerce, they make a traffic of all the humane, all the moral virtues; the most trifling things, those which humanity would demand, are there done, or there given, only for money.
The sentence refers to customs in Holland, a particular country, where he claims people are moved only by the spirit of commerce. The word "there" refers to that country. The sense is
In Holland, the humane, the moral virtues, even the most trifling things, are done or given only for money.
The sense of "given" is "are given up", as you thought, or "given away". That is, those things, important or trifling, are not given away freely or generously.