Common squads->Unique squads

[Pumpkin_King]

I was thinking about a comment made here a few weeks ago, that the fact that there can be more than one common squad is factored into the cost of the squad. Now, I know that there is a small section of Heroscapers that do not have the funds to buy more than one of every set. What might be a rule of thumb, a percentage maybe, that you could reduce the cost of common squads to make them unique?