Sure, but it depends on what you mean by "virtual store," "coins," and "buy." In a more serious vane, it would help peolpe give you a useful answer if you are more specific about what you are trying to accomplish.
Are you trying to collect in-app payments from users and have them fulfilled through the Android market or iTunes? If so, there's no direct integration available yet in AIR. I did see that the developer of Cognicube devised a system through which he sold additional features. It looks like he did it by putting special non-free apps on the marlet that the free app could detect somehow.