Would you consider buying a used canon 5d Mark II in mint condition with 120 000 shutter actuations for 500$? The seller is a nice lady, she is a professional phototographer. Here are some photos of the camera that she has sent me.
I tend to equate shutter click counts with car mileage. To me, your question's equivalent car shopping question is: Would you buy a 2008/2009 used car with 120,000 miles on it for 1/5 of what it went for new?
You may also want to look at this website:
The graph is based on a survey from 5DMkII owners, who navigated to the site themselves, about when their shutters failed/are still alive. The page states:
Average number of actuations after which shutter is still alive: 137,709.5
Average number of actuations after which shutter died: 171,076.9
It looks like the failure rates begin to increase right bang on the 100,000 mark, which is the typical lifespan spec for Canon's shutter mechanism, iirc.
Based on a Kaplan-Meier statistical analysis of the submitted data, you have about a 3 in 4 chance of making it to between 250,000 and 500,000 and a 2 in 3 chance of making it to between 500,000 and 1,000,000 actuations. There's only about a 1 in 8 chance that the shutter will fail at between 100,000 and 150,000 actuations. Canon rates the shutter of the EOS 5D Mark II at 150,000 actuations.