Price of the product obtained from the attributes without main price

[Lopik]

Where in the code I could change the calculation of the price of the product? I would like to be summed only the price of the attributes and not the price of the product?

 

For example - I sell dresses:

The product is priced at 30 Eur (and that price I want to be displayed in the product)

 

I want to have the product attributes:

Size 36 - 1pcs, 2pcs, 3pcs ... etc.

Size 38 - 1pcs, 2pcs, 3pcs ... etc.

Size 40 - 1pcs, 2pcs, 3pcs ... etc.

 

But with such a configuration, when choosing the number of units of the attributes I get the price to be paid, plus 1 piece more.

Is it possible to change this so that Presta always reduced the price of one piece?

 

Example: http://lopik.desperadowholesale.com/Hurt/product.php?id_product=10