Dont
waste
your
money
CO2 is not needed for growing unless you are growing in a sealed room that gets zero fresh air replacement. It’s not something, for a home grower, to ever add to their grow space.
I know people think they will get massive yields, but the reality is....you won’t. You won’t even notice a difference unless you have grown several crops of the same strain and know what is the base volume of product you know you will get.
Save your money or invest in more lighting.