I've replaced mine for $10 with a ebay screen from China. That was for a old point and shoot camera. I've also noted that prices were much higher for modern DSLR's. As long as you have proper tools, JIS screwdrivers, not phillips, its just a simple job but requires cleanliness and patience.
I see a 5D MK IV new replacement from China for $189 which indicates that parts from Canon USA are going to cost much more.