add discount field to payment form?

Hello Ray,
I built a payment page (with your help, of course) where the user pays to register to a website and play a game.
This works as expected.
But now the customer would like to add a coupon (discount code) to the form.
I simply would add an input form where the user enters the coupon code. The code can be a static value, so there is no need to handle it with the database. Maybe in the future...
But now it would be enough to just enter the code in the coupon field to set a discount price.
Can I add this feature to the current page without re-do it from scratch?
Here is the page (private):https://www.landgame.eu/xmas-room/registrazione.php
Please note I'm still testing it (so the real payment is 0.01 EUR per registration).
Credentials to see the page are attached as private attachment.
Thanks for any help, Ray.

tony

Yes. Just add the coupon code field to the form. Then use the server behaviors panel to save the form value into the session. Lastly, update the cart object to add a discount based on the session value.

Originally Said By: Ray Borduin

  Yes. Just add the coupon code field to the form. Then use the server behaviors panel to save the form value into the session. Lastly, update the cart object to add a discount based on the session value.  

IS there a way to update the Price displayed before submitting the form?
TIA
Tony

You could add a new "Apply coupon" button that refreshes the page and shows the updated discount so they can see the new price before pressing the checkout button.

Originally Said By: Ray Borduin

  You could add a new "Apply coupon" button that refreshes the page and shows the updated discount so they can see the new price before pressing the checkout button.  

I'm almost done, but I can't make the cart value set to 0 with discount.
Example:
The regular item price is 0.01€.
The coupon should allow to set the item price to 0,00€ (free).
But the discount work only if the resulting price is not 0.

Example:
The regular item price is 0.02€.
The discount is subtotal (0.02) minus 0.01.
This way it works and I get the cart to be 0.01€.

Again, if I set the price to 0.02€ and the discount to subtotal minus 0.02, it doesn't work and I get the price 0.02€.

But how can I set the price to be 0 with a coupon code?
Is there something else to look at in the cart definition?

Or perhaps is Paypal that does not allow 0 money transactions?
How can I solve this problem, in this case?

TIA
tony

Paypal won't allow a zero transaction... You would have to add code to skip paypal and process the order without payment when it is free.

Originally Said By: Ray Borduin

  Paypal won't allow a zero transaction... You would have to add code to skip paypal and process the order without payment when it is free.  

If I understand corretly I should skip the code if the discount code is correct and go to another result page to insert the data in the db.
Is this right?
TIA
tony

You could just skip the paypal payment portion and not create a separate page. You could do a separate page if that helps you though. There are multiple ways to do it, but however you do it, you can't use paypal on a zero dollar payment.

Originally Said By: Ray Borduin

  You could just skip the paypal payment portion and not create a separate page. You could do a separate page if that helps you though. There are multiple ways to do it, but however you do it, you can't use paypal on a zero dollar payment.  

Hello Ray,
is there a way to skip the ecart server behaviours without breaking their editing ability?
Something like the screenshot attached?
I'm trying to do this but it doesn't work.
TIA
tony

never mind.
It seems to work, indeed.
Tony