Help pricing NPC spellcasting

[thorimar]

I have a player that wants to have Axiomatic Creature cast on them. It is from the BoED (pg 91) and is listed as an Archon spell. I don't have BoED in my library. Can anybody tell me the basics of it? And who can actually cast it? Does he have to find an Archon to cast it? Based on DMG pricing for NPC spellcasters, it would cost 10 gp x spell level x caster level, which in this case would be 10 gp x 8th lvl x 15th lvl (guess) for a cost of 1200 gp. But this seems way too low if the spell requires an unusual spellcaster. Any and all help would be appreciated.

Tim

 

[Maleketh]

Axiomatic creature has "Archon" as a component, meaning that it can only be cast by an archon. Furthermore, the spell requires a 10,000 GP diamond, which must generally be paid for by the PC, and an expenditure of 1,000 XP, which translates into an extra 5,000 GP added to the cost. The PHB states that spells costing more than 3,000 GP to cast are generally not available, so it's up to you as DM to decide whether your PCs can pay to have this spell cast - assuming they can afford the 16,200 GP price tag in the first place.