yeast is a unicellular micro organism in the "fungi" family. and sugar water is sugar mixed with water. not to be confused with water sugar, which is water mixed with sugar... sorry i just had to...
you get about 0.75 litres of C02 per g of sugar used, pretty good technique for the cost in the appropriate situation
Is that per Gram of sugar used or gallon? How much water yeast and sugar would be used for a 1ftx2ftx2ft space?
vinegar and water will only give you a quick burst of CO2. Yeast makes CO2 for a longer period, but it stinks up your grow room...