How to create a "points shop"?

I saw this cool idea for making a points shop in the "tips and tricks" section, but it did not give a good description on how to make one. My questions:

Thru the Admin Panel, I know how to give ppl points, but how do I take them away?

How could someone buy something like "1 Sticky Post"?

Could my site automatically subtract points from someone once they buy something?

Here's a model example of what I want my shop to look like: http://combatclanz.com/forum/index.php?action=shop;do=buy

Well right now there really isn't really any option for that but you will have to do it yourself.

oh. nevermind then.