Create Coupon Codes

[kaseyclark]

We would like to offer a $10 Off coupon on FaceBook for new persons who "like" our page.

They usually either order custom items which are invoiced through PayPal OR purchase through our store  

I know that we can just deduct the $10 if they are invoiced.

How would it be done if they purchase through the store?

Is there a code to give them or ???????

Thanks in advance for your help.