Well, Keltham hasn't seemed all that interested in saving Keltham money either!  But Carissa doesn't have an infinite quantity of spending money with her on this trip, unless you count unlimited Wish diamonds that can only be spent if conditions of secrecy can be created around that and you know what a noble Efreeti plans to do with them, and you may need that money for other things.

Like an IOUN STONE.  Does Carissa Sevar want an IOUN STONE, a vibrant purple prism that stores up to 3 total circles of spells?  Nobody in Golarion has been able to make an IOUN STONE for a long long time, but maybe they just didn't have enough Spellcraft and weren't soon to be INT 29 and didn't have a magical simulator of magic physics!  Also her cult members would probably be pretty impressed if she walked in with an IOUN STONE orbiting her, at least those of them who knew what an IOUN STONE was.

Well, Keltham hasn't seemed all that interested in saving Keltham money either!  But Carissa doesn't have an infinite quantity of spending money with her on this trip, unless you count unlimited Wish diamonds that can only be spent if conditions of secrecy can be created around that and you know what a noble Efreeti plans to do with them, and you may need that money for other things.

Like an IOUN STONE.  Does Carissa Sevar want an IOUN STONE, a vibrant purple prism that stores up to 3 total circles of spells?  Nobody in Golarion has been able to make an IOUN STONE for a long long time, but maybe they just didn't have enough Spellcraft and weren't soon to be INT 29 and didn't have a magical simulator of magic physics and weren't trying hard enough!  Also her cult members would probably be pretty impressed if she walked in with an IOUN STONE orbiting her, at least those of them who knew what an IOUN STONE was.