Ooooh doggy, that's a big ol can a worms. Subs are only on sale for a limited amount of time, which has passed for 2012 (they're usually on sale beginning with the start of SDCC and ending around the end of August. The sub exclusive figures (1 per year) are the most costly because Matty won't re-release them, and there are only as many of each of them as were sold subs for that year. 2010 Wun-Dar, 2011 Preternia Desguised He-Man, and this years 2012 Shadow Weaver. The line is costly, but it looks to ma as if the secondary market is lowering it's prices, at least from what I see on e-bay. Mattel won't be re-releasing any figures from now on (Man-E-Faces is the first to be affected by this rule, so any figures that were released after him won't be returning) but matty has gone back on their word several times with little to no explanation. He-Man, Skeletor, Battle cat, Panthor, and maybe more eventually will be available year round on Matty though.
Whew! That's all that comes to mind at the moment.