(Spoilers for any campaigns set in/near Sandpoint, obviously!)
According to Sandpoint's settlement stat block, the highest-level spells available for purchase from spellcasters in town are L 4.
However, according to Sandpoint's write-up (Rise of the Runelords AE), the listed spellcasters have a maximum caster level of 4 ... which is definitely not the caster level 7+ needed for those afore-mentioned L 4 spells.
So who are these (somewhat) higher-level spellcasters in Sandpoint, and where can they be found?
One suggestion that I've heard is that various travelling spellcasters (possibly from Magnimar or Riddleport) come through town regularly once a month, and make their services available to anyone who wants to hire them for specific spells.
Does anyone - JJ or otherwise - have any useful input on this curious issue?
Scrolls work as standard magic items, of course. The thing is, though, that spellcasting for hire includes the actual casting of the spell in question (without any risk of flubbing one or more checks, unlike scrolls).
The short answer, there are none. So you have one of three options:
1) Ignore it
2) Up the levels/alter a few NPCs. I did Abstalar Zantus (changed to an oracle), Brodert Quink (changed to diviner / loremaster), and Ilsorai Gandethus (added levels of arcane trickster).
3) Add in some NPCs of your own. I did a couple of these as well.
If you dig thru the Rise of the Runelords forums you'll also find tons of community content expanding upon Sandpoint.
If it hasn't been wiped out yet in your game, Windsong Abby has some mid level spellcasters, so you could pull a few from there. See more on it from Shattered Star, Beyond the Doomsday Door #64.
You could have Casamir Azmeren of Windsong Abbey visiting Sandpoint semi regularly.
Just wing it. The players should not be seeing NPC stats anyway. Maybe you could level up NPCs as needed to keep the story going; maybe an NPC has a magic item that has the spell the PCs want to buy. Don't let game mechanics get in the way of the story.
The two easiest fixes.
Ilsoari Gandethus - Wizard 7
Niska Mvashti - Oracle 7 or 8
other ideas could be amusing such as
Aliver Podiker - Alchemist 10
Brodert Quink - Wizard 7
Hannah Velerin - Cleric 7
(I've actually toyed with the idea of making Hannah a villian...)
Alternately, as some have suggested, ignore it, its a guideline for the average.