Examples of non-zero-sum games include:
Two parties trading: both may simultaneously gain by a transaction.
It can be assumed that the buyer attaches a value to goods purchased which is higher than the price paid.
At the same time, the price paid to the vendor can also be assumed to be higher than the value, to the vendor, of those goods.
The loss of a particular ship may cause a setback of considerably greater value to the enemy than the cost of the materiel used by the attacker to destroy it.