This MTM Hydro SG-28 high pressure spray gun (rated to 4,060PSI) is a much less expensive but still very valid solution for those that may not care about having a swivel. This is a little lighter than the Mosmatic solution and looks and feels very similar. I don't know this for a fact, but I'm pretty sure they are all made by the same company.
You have these buying options:
Spray Gun Only
Added Quick Disconnects to connect to your pressure washer hose.
1/4" MTM Stainless Male Coupler
3/8" MTM Stainless Male Plug
3/8" MTM Stainless Female Coupler
M22 to 3/8" MTM Twist and Plug
Added Adapter if you have a pressure washer hose that is M22 15mm instead of the normal 14mm standard connection