It should be the same price for both. Let the selling price be a, the compensation purchase price be A/( 1-0.2), and the earning purchase price be A/( 1+0.2).

If the selling price is 60, the compensation purchase price is 60/( 1-0.2)=75, and the earned purchase price is 60/( 1+0.2)=50.

So in general, we lost 75+50-60×2=5 yuan.