Hi there @Lavender!
Welcome to the Community and thank you for posting your question here regarding BigCommerce. Hopefully we can find a solution together.
My initial guess is the way it's being rendered there isn't data available for the product.price.without_tax_value. I'm not sure how product price is stored in there BigCommerce Admin unfortunately.. but i would assume one of the following in this BigCommerce documentation would work. It is also important to use the right plugins and setup for the right Stencil or Blueprint Theme.
Please also make sure the event.price is a lowercase E as this is case sensitive!
Let me know if that helped!
Alex
@Lavender did you ever find a solution to this? I’m having the same problem but the documentation isn’t much help.