I think you may see some of the pets spells come down in prices over the next few weeks. The Splitpaw patch has now stopped pets from scaling by tier, so the app2 version of a pet spell is pretty much as good as Adept3. The upside is that pet damage was increase along with pet hps, but tier increase seems to be just for look now.
I have noticed some tanking ability increases from my pets (all Adept3), but my guildy friend has no problems with his app4 pets either. Odd, and kind of ridiculous, but what can you do.
Most of the price gouging from Summoner spells is also from the influx of froggy players. Give it a few weeks, and prices should become more resonable. Remember to check the broker everyday also. Those outrageous prices are only the lowest prices that people won't buy them for. After a few days with them not selling, most people will lower the price just to clear vault space.