Basic colorectal cancer screenings cost around $100, but like all health care there is considerable variance in what people pay. You are implying that we should test all people for all possible problems which is simply not practical and probably not even possible. Testing is instead based on health condition and history.
The specific details of why this money would be a waste that could be better spent elsewhere are in the report which is a good read: http://sciencenordic.com/should-colon-cancer-screening-start...