Facebook fan gate is the popular term that refers to Facebook page owners barring non-fans from accessing certain contents in their fan pages. It is a very powerful tool to gather fans and reward your followers.
tackthis' Facebook shop app also gives you the ability to fan-gate your shop. In other words, if you enable tackthis fan gate function, people who have not 'liked' your page on Facebook will not be granted access to your stores. This means, you will be able to make a facebook shop with exclusive, fan only access to rewards your best customers! How cool is that!
After that, an option to upload your fanpage banner will come out.
Fanpage banner is the image that non-fans will see when they visit their shop. So make sure you put something along the line of “like us now” somewhere inside.
tips: fanpage banner should be of 520px width so that it appears just nice within FB's iframe.