Paste this in your browsers console on promo page:

for (product of gogData.promoProducts) {
console.log(product.title + ': ' + product.price.amount);
}

I don't know how well that fits your needs, but maybe it will somehow guide you. :) You can retrieve that data from the HTML source code too - search for gogData.

edit: Adalia's way is also good for owned/not owned games. :)