Although there is a state run company based in Beijing that might take you for half that price if you can manage to deal with their bureaucracy .
Few destinations hold as much traveller kudos as North Korea.
Pyongyang, despite reputably being the least visited capital on earth and North Korea's stance as the ultimate 'hermit state' firmly intact, it is however far from difficult to visit and tour.
There are essentially two ways you can see the DMZ.
The first is travel to one of many observation points along the border and look over.
To/from China there are many ferry routes from East coast cities all heading to Icheon (most popular are to/from Dalian, Dandong, Qingdao and Tanggu/Tianjin for Beijing.