Problem with Card

[Goodspeed]

Hi all.
I have the following problem. When a customer places a product in the shopping cart, the price is generally correct as € 0.99. There is, however, a quantity of 100 units the price changes to € 9,900.00. which is of course wrong. 've Already looked everywhere I made ​​a mistake, but unfortunately I do not find him. Please help me.

For better understanding, I once made ​​three pictures.