I have #4 mk 1. They run about $150 and up. It all depends on whick mk. you get.
Like Mausers,nagants etc. there were a bunch made. Some more rare than others.
www.southernohiogun.com
www.centerfiresystems.com
www.centuryarms.com
These are just a few you can get an idea from. But, you need a c&r license on file with them. If you go to a gun show the prices are pretty much the same depending on condition.