Forget the baking soda and vinegar thing, and I think its impossible for CFLs to PRODUCE CO2, carbonate water loses its carbonation after being exposed to air after a few hours (ever had coke without fizz... how long did that take?) but if you are on a budget and cant afford CO2 tanks you have got to check this link out...
http://www.bghydro.com/BGH/itemdesc....ACO2EF&eq=&Tp=

This excellofizz is probably the cheapest way to get CO2 throughout the flowering cycle, unless you want to buy 3 pounds of bicarbonate soda and a couple gallons of vinegar and stink up the house.... this Excellofizz stuff is amazing and hasslefree. -Peace