Add custom pricing?

[theterri41]

Hi!

So I use PrestaShop together with a module called "tshirtecommerce".
And I've written a code that calculates the amount of custom text and updates the price accordingly.
The problem is that I would like to save the custom calculated price to the product so when the product appears in the checkout stage, the custom price will be combined with the basic price.
For example:

A shirt costs 10 dollars.
The user adds custom text that amounts to 4 dollars.
When the user adds the product to the cart, the product should be 14 dollars instead of 10 dollars.

Thank you in advance!