Hey adahars37,

First thing to buy, since you grow where you live and sleep, is a Carbon Monoxide Detector. They look like smoke alarms but monitor CO level; too much it goes off and you and yours can wake up instead of not.
While the chance of killing yourself using the typical 10lb bottle of CO2 is small, don't take any chances.

Typical regulator and emmitter is about $150, plus tank and refills. Try to get two tanks and I would use two different suppliers for re-fills.

BTW: If you wanted your (human) co2 output to help your plants, you would need to sleep in there while the LIGHTS are ON. Your plants have no use for co2 during the dark period.