SN10224 was sold on eBay early in 2006 for $1,375.
The owner actually used this very website as reference material for prospective buyers to learn more about Computer Space, quite an honor!
The machine is apparently in good working order, though the tubes take a while to warm up on the screen. Also, the seller did mention that although the cabinet is in good shape, there are a number of small scratches. Still, for a fully working machine, $1,375 is a good price. The original site detailing the machine can be found here.