Although they aren't so easy to find, a more normal price for a used MK23 is more like $1700. I've seen them as low as $1500, but that's a steal. Not long ago CDNN had them new for $17??. This price you're looking at would be a good deal if the case were one of the collectables, had a bunch of extra magazines or was maybe an original HK Maritime Finish (rare... ugly but rare).