Can you mix Broad, Phrase Match and Exact Match types in a campaign? Am I right in thinking that Phrase and Exact lower your Cost Per Click?
You can mix them within a certain campaign. I would test all three and see which one yields the best total ROI. Then setup two campaigns, one with proven ROI and one to test with so your numbers don't get skewed. It's not neccessarily true that phrase and exact matches lower your PPC. For example if you are bidding on widgets for exact match it might cost 50 cents where as if it were a broad match it would show up for big widgets which may only cost 10 cents.