"I'm well aware that this is a venerable and high quality art, and not so widespread as ones like Martensite Crucible."
"Plus," Ning adds, "It's a core cultivation manual, not merely an additional technique."
Wen nods pleasantly. "Indeed, a much higher class of art than most. Though I would hesitate to place it on the same level as formation or alchemy manuals. The Three Jades Sect is, after all, not the only ones who have it..."
"I think you'll find anyone else selling this manual to be in much the same constraints as us. You're lucky if you have the chance to get it for spirit stones at all."
A fierce round of polite haggling ensues; Wen takes the strategy of fussing over details of the non-proliferation oath, which she relents on after Ning starts getting frustrated.
"...Fine. It's not like we lack spirit stones. One thousand five hundred to the sect plus a favor of two hundred fifty to the technique hall directly is acceptable, if we can adjust the usual oath as we discussed. We're going to be travelling far, and returning for dispensation from it would be troublesome."
"I sense your sincerity and righteousness, and I'm sure my Elder will agree to this adjustment."
"Here, the first part of the payment ahead of time."
And then there's going to be some fussing with oaths and security seals and weights and scales and Wen scoffing at a patronizing compliment of 'beasts having learned civility' from the stone-auditor.
And then they have a large scroll - not merely a paper manual - sealed with some sort of talisman, and can leave.