1) Shadow Weaver (by far)
3) King He-Man
4) Preternia Disguise He-Man & Unnamed One (probably tied)
Of the non-exclusives, Fisto, Teela, Sorceress, Whiplash, Battle Armour Faker are probably the most expensive, with Beast Man, Kobra Kahn, Scareglow and some others following close behind.
Not sure how Oo-Lar will fit in, butt I assume above King He-Man at least, but not as much as some of the more expensive non-exclusives.