by Faso74it
Think of it as:you play cards and accumulate influence points. Add your bonuses/maluses from reputations, and other effects. Now you have a sum to spend. After you've bought a unit, you subtract the cost of it. If you want to buy another one, you can use the influence points left. If they're not enough, you can play more cards to increase them.
This way, the reputation bonus gets counted only once.