It’s called “secondary” in Bootstrap, and “Buy Now” is legitimately the secondary option here.

It’s relatively rare a person would rather just buy without trying first.

Cancel would be the “danger” class in Bootstrap, and I would bet it’s the color of the actual “Never Mind” option somewhere in the larger version of this screenshot. My hunch is there’s an X where you can simply close this window. Unless it’s an app that requires a subscription to use in which case the close option is to close the app.