Do we actually know if people are paying that? AWS wants to make sure they can always fulfill orders on regular instances, so whenever they're running low on availability they'll just hike the price enough to shutdown enough spot instances. I doubt people actually pay that price. Or it's rigged.

I don't use spot instances anymore but if I recall correctly these random spikes are rather usual, no?

I guess they may not be. Makes it a pretty murky system then. Amazon know what our max bids are and they're adjusting the price. They obviously control supply, and that's dictated by on-demand usage, but the price itself must surely be the lowest bid out of all those that still have a machine.

In terms of the stability - it's generally really solid. You sometimes get spikes, but I've never seen anythingike this (and it's been going on for a few day). To give you an indication I had a box that was shutdown that had been running for about 1.5 years.