For those of you who aren't leveling for a specific artifact, you have the option to sell some of your keystones and make a profit. Personally, I think this market is in for some big shifts soon. Right now it looks like prices are primarily being driven by other Archaeologists. What seems to be missing is the competition from pre-raiders. Some of the keystones can be used in dungeons to buff the group. Right now this includes Tol'vir, Dwarf and Night Elf keystones. Things could get interesting once you have dungeon players competing for keystones.
I've done a bit of research on my realm and right now prices don't seem to be trending with the perks very well. Tol'vir keystones are the most valuable, since they're needed for three iLevel 359 epics as well as the new Alchemy mount. Today on my realm they're selling for 1000g each. This makes sense and I fully expected them to be the most expensive. However, I'm also seeing Draenei keystones going for 300-400g, Vrykul for 350-500g and Nerubian for 500-700g. None of these races have epic artifacts or dungeons they can buff, so I'm not certain why their keystones are inflated. I can only assume players are pricing them based on the Tol'vir without realizing that these other races don't have the perks to justify such a price.
I'm also seeing Troll keystones at the lowest price, which surprises me considering how many players are after Zin'Rokh. Now it's possible those folks are getting all the keystones they can possibly use through their own looting, but I kinda doubt it. Either way, Troll keystones are hovering around 100g, pretty reasonable for anyone working for an epic 359 sword.
Dwarf keystones are about double that price, which I take as evidence that dungeon folks are probably influencing the price to some extent. Night Elf keystones are in the 100-150 range, which seems to fit in with the Dwarf pricing. Dwarf keystones are used in more dungeons than Night Elf, so the demand for them will be higher than Night Elf. All three of these races have one 359 epic, which puts them on even footing with diggers. Therefore the variation is likely tied to the dungeon buffs.
Based on what I'm seeing here, I think the prices for Dwarf and Night Elf are too low. Heroics are very challenging right now and not enough players are using these buffs. As word gets out, prices should go higher for both of those races. On the flip side, I think prices for Draenei, Vrykul and Nerubian are too high. Draenei especially should be dirt cheap, there are no epics tied to this race. I suspect the prices for these races have more to do with their Outland/Northrend place in the leveling chain than their loot potential.
If you're interested in selling keystones, offload some Draenei/Vrykul/Nerubian keystones. I would hold onto the Dwarf/Night Elf and see if the prices go up once more people are running Heroics. Interest in Archaeology should start to dwindle around the same time, as more players are filling their time with dungeon runs and have less free time for digging. Tol'vir artifacts are already worth a boat-load, so go ahead and sell if you don't need them.
If there's anything I missed here, feel free to share it in the Comments!