Found this at the InterRealm Ranger's Board, it lists the location of all the Ranger spells and their AP cost at the merchant.
Ruj: Spirit of the Shrew - 72 points
Miragul's: Pack Shrew - 200 points
Mistmoore: Fire Swarm - 410 points
Tak: Call of Ice - 450 points
Guk: Feral Form - 650 po