are the buttons that you can buy for 9bucks good test kits for checking on CO leaking from the exhaust of my gas appliances and around the house or would it be better to invest $150 on the meter tool from home depot?
Most people buy 2 good First Alert CO detectors and plug them in the wall. One downstairs and the other in your bedroom. A commercial grade CO tester/meter costs several hundred $$ from a heating wholesaler.
I use this one: http://www.ueitest.com/product-co71.html
Those test vial units etc can go bad with age and I would not trust any cheap CO tester. That UEI I have is tough as nails and works very well. Not sure what it costs now but you may as well buy a good one or the process is unreliable/inaccurate.