How to surcharge orders?

[z72diego]

Hi, of course thanks to all who give of their time for a while to help me.

 

I need to modify the code of PrestaShop to accomplish the following:

 

When a customer places an order less than $1000, automatically apply a surcharge of 30%

[For example: an order of $300, as is less than $1000, in final amount would be $ 390 (300 x 1.3)].

 

And when a customer places an order of $1000 or more, that prices have no surcharge.

 

From already thank you very much and I hope I explained clearly!

Edited October 30, 2012 by z72diego (see edit history)