If you're a RDM, then either grab a couple of level 40 DRGs and do Royal Jelly, or grab a couple of level 40 NINs and/or BLUs and do Under Observation. Both BCNMs are super-easy as long as you have decent gear (not even top-notch expensive stuff) and intelligence. Read up on strategies on the Wiki and you'll see.

They're also going up because a lot of people simply don't have a need to do BCNMs anymore because of the other methods to get gil that Abyssea brings, and beastmen seals don't drop in Abyssea so they aren't as prevalent as they used to be. The price is deceptively high for how easy to obtain those scrolls actually are. Demand got higher than supply so the prices skyrocketed. Don't think that just because something is sold on the AH, you have to buy it.