Hello from the Velo DevRel team!
You should be able to do this with Wix and Velo.
First, I would grab the input field with the .value() method and save the value to a variable.
Next, I would perform some kind of check on the value to see if it was equal to zero.
The most straightforward way to implement this would be with an “if/else” statement, where the “if” case either hides the button or replaces it with a separate “Contact” button. The “else” case in this instance would keep the button the same.
All of this could be implemented inside of the $w.onReady() function that comes already set up by default with every Wix site in Dev Mode.
It’s hard for me to speak to the specifics of your site without having access to the site and code you’re working on, but hopefully this is enough to get you started!
Thanks,
Rob