Thank you for the tips and price range. Also when it does sell I will double box it just to be safe. I was always worried about shipping this lamp because I've heard how fragile it is.
I'd politely disagree that a lava lamp is more fragile than a geyser. Lava lamps routinely arrived to stores in fine shape. Many Geysers arrived broken, still in the boxes from the factory.
I'd advise you - if I may? - to check the small print of the courier company's T&C very closely - as over here in the UK glass items are pretty much un-insurable in the post, though as TLC indicates, some companies like FedEx may cover you?
When I ship fragile lamps, I do all the double-boxing and bubble-wrapping, then before I ship it, I take a look at the item and assume someone's going to swipe it with a baseball bat - that's the road test. Then do the final sealing-up.