Why is this even a debate about expense? Even if it cost the government $0 to store data on all americans and send agents to search peoples homes and question them it would not make it right for them to do it.
This is a basic question of what freedoms individuals have. If you make the laws so complicated and or secretive that no one can comply with them then the entire system fails. You have 3 letter agencies running around selectively enforcing overly complex/secret laws then the very foundation of what the law is meant to do breaks. Selective enforcement equals political influence equals the Rule of Men, not the Rule of Law.