You cant sell 100 copies not because the logistics of that would be moronic, but because you can not find 100 stupid people to pay 1800$ license + 100$ monthly fee for that script.
Actually, even if you jv with the best marketers in the world - and you can add Frank Kern, John Reese and other gurus with email lists full of non-knowledgeable people- , i highly doubt that you will be able to sell even 10 copies, your original "limit".
Your script is worth around 97$ if you sell a limited - but high- number of licenses, let's say 100 copies.
If you limit the number of copies to be sold at 10, your script is worth around 500$ at most.
For 1800$, a person can get custom created a much better script than that one, and he will own all the rights, the source code, and can resell it later, and do whatever he wants with it.
Paying 1800$ for that license is really really stupid.
(And i haven't even bring into discussion if you can actually make money with that script to justify the price tag )