Probably $800 with printer rebate by next holiday sale.
If it were $500, I'd have to consider it carefully, since my only use for it is on my telescope. At $800, I'm a definite no way.
The problem I'm trying to solve is that my scope's widest settings combined with my 7D Mark II doesn't result in the moon fitting in the frame, so I have to shoot panoramas during lunar eclipse events. Also, my 7DII doesn't have an articulating display making it pretty hard to use in some positions when the scope is on the mount and looking up. But that's the only problem I'm trying to solve. I've considered solving it with a smaller scope,
which I can get for about $399. But I'm not that fond of RCs and my current scope has almost four times the light collection area so I'd rather just have a larger sensor. I still have my old 5D but the sensor isn't the best and the big problem is that it doesn't have live view so it's really, really hard to focus. No articulating display also.
But how much am I willing to spend to make shooting lunar eclipse shots easier? Not that much, especially when I got this with my 5D and my current scope. It's not easy to beat this.