how much U$s is 99000 nx?

Of course, one has to wonder how those sites can charge less than the only producer of NX does...
Ah, but who cares, we'd all buy a stolen TV or car too, if it were cheaper, right?

Anyway, $99 is a lot of money, but, if you are going to ward-enhance your gear at all, it's a better deal than $11.9 each.
Unlike many real-world "bulk prices" which make you buy more of a product than you could ever use, just to get the lower per-unit price, here a quantity of 11 is quite realistic to use up on a single weapon. Would likely take you to 7 or so stars.
Are you willing to pay $99 for an estimated extra 20-24 attack? That's your call.

i've wondered for a while how they get those NX prices, i know how hackers do, but i don't think meso sellers follow suit in the methods.