As I started buying things in the marketplace, I quickly found a few users that I really love, and would definitely want to buy every new piece of art they publish. But sadly, at the moment there is no way to be notified of that in roll20, I'd need to check the store manually each day (which I don't, it's way too much of a bother) and find any new releases on the marketplace which isn't that well organized to begin with. So, my suggestion is a way to subscribe to an artist, to get a notification, either by roll20 or by email, each time they upload something new.