Follow his Facebook and have it listed to show first in your feed. They will post when a shipment hits the shelf. With refurbs he only gets what was repaired so selection isn't always going to be every model every time, and sometimes they sell out super quick (within minutes). So ya, follow his page, wait for updates, drive yourself crazy with the wait!
The best option is to sign up for the newsletter on the website, so there is no chance of it getting lost in a FB feed. Make sure you have it set to go to your inbox, not junk mail. You will only get a few newsletter's a year, so its not like you get your email address flooded with spam.