Creating a Buy Back Service

Hello,

I am currently designing a site to function as a Buy Back service. Essentially, the only function different than a standard ecommerce site would be that the users do not actually have to pay at checkout. Instead the checkout page would inquire for some custom fields such as asking if they would like to receive payment via PayPal / Venmo.

Is this possible? I have already set up a products page.

Here is my site: My Site