He is not selling MULTIPLE COPIES of the script, he is SELLING THE SCRIPT. He may keep a copy and continue to make use of it, or sell it outright.
The price seems fair IF you have the ability to use the script, especially in a short amount of time, at least until the big G finds a way to detect and ban the use of the script.
I personally have not tried to make a network of fake blogs or whatever else you can do with this script, but I CAN see the possibilities...
Good luck man, not something I can afford, or use, but could be useful to someone!