Why my form does not redirect to PayPal?

I've copied a form that worked last year for our conference. This year the submit button will send me to the Thank You page but does not redirect to PayPal when an amount is due. 

I checked your form and the problem is that payment value is not populating properly, it's always zero and that's why your users are not redirected to PayPal, there is nothing to pay.

And that's because of your calculations field:

You shouldn't use conditions for that:

I assigned calculation values to your products:

And inserted that field in form calculations:

And it is working as intended.

Please check and let us know if you have any further questions.

Thank you!