I don't think there is really a price for these things, its generally whatever someone is willing to sell it at. I have Q190 beetroots that I won't sell, but that doesn't mean that someone else won't sell beetroot of that quality for cheap.
Early world exploit: Put your hearthfire inside a cave, then hold shift to position a claim right in front of a cave. After 8 hours the claim will be unbreakable. Since your hearthfire is inside the cave, you can still get back inside, and leave, but nobody will be able to enter, effectively making you unraidable for the first 3-7 days. Enjoy
Im willing to hear offers from individuals who are willing to sell. Just figured I would get the opinions of those more knowledgable than myself first.