Tracking Referrals From A Gallery

In a month or so I should have some prints going up in a gallery. Out if 4,000+ images they'll have rom to display 5.

Is there any way with FAA to setup any kind of tracking that could track sales back to people referred from the gallery, a unique URL or anything like that?

If the gallery would get paid for referred sales they'd probably be ok sending people to the site but if not then it would probably just be limited to prints on display.

A discount code could work but is there any other way to do it?