Input select with text: Yes / No – problem

I have a box with the choices: Yes, please and No, thank you.
How to make it in the form so that after the user selects the option: Yes, please, e.g.: some amount is added to the calculation?

In forms i have something like that:

Apartament typu Easy (max 4 osoby) w Silvia Residence – 500 z? apartament/pobyt
[select Apartament-easy “Nie, dzi?kuj?, wybieram apartament Aria w Post Residence@@Nie, dzi?kuj?, wybieram apartament Aria w Post Residence” “Tak, poprosz? apartament Easy w Silvia Residence@@Tak, poprosz? apartament Easy w Silvia Residence”]

If you set it in advanced costs under the option: Yes, please – some amount.
Ultimately, it does not add up and shows 0.

Thanks for any advice!

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