User counter - integrate with points system

[Python2]

Basically what I want is for my members to each have a unique link. It could be something like this:

site-name.com/click.php?uid=5

Then each time that is clicked on I would like it to add 0.5 points to the users total points. However I only want it to add that amount once per ip address. Perhaps use cookies or something so that it can only add the amount once.

Its pretty simple im sure..I just dont know how to do it. It doesnt need to have any admin section or anything. Just needs to be kept simple.

Im willing to pay $10 to the person who does this

Thanks