On page view, minus credit

[ncaawallpaper]

Hello all, please, I need a little help with this script. I am charging one credit (credits can be purchased, but that is unrelated) for view of a certain page. I need help in figuring out what php I need to add to each of the articles I want to charge for. Here is what I would like:

 

On view, if $balance is more than 0, subtract one credit. If $balance is less than 0, have page redirect to, oh for sake of example, google.com. Also, not sure if it would change, but I would also like the code for the same thing, but instead of $balance, if it were just a variable called VBalance.

 

Thanks it advance!

[mrMarcus]

if ($VBalance > 0)
{ $VBalance = ($VBalance-1); }
else
{ header ('Location: http://www.google.com'); exit (0); }