Select the options, click the offer button, fill the offer price and other details
in the offer window.
Submit the offer, you will receive an email for this offer, we will review it to
see if we can accept it.
Go to the offer detail page, you will see your offers list. if it has not been accepted,
you will see the checkout button is grey out.
We will review the offer, once we accept it, you will receive an email with link,
when you go back to the offer page, you will see the checkout button is avaliable
now, you can just follow it to checkout.