Money could be an issue, but my 2 cents is to start saving for pressurized CO2. I know some people like them but for me I had nothing but problems. Cloudy water, yeast getting into the aquarium, BGA all over the place & yes leaks. It is messy time consuming & unpredictable. I almost gas fish on several occasions. The ph can be unstable which is related to under fertilization or over, gassing. The bottles can explode as well making a bad mess.
Now I know there will be defenders of DIY coming to join this thread soon & all I have to say is I would never go back. My tank is stable ph is good ,crystal clear water & thriving plants with NO ALGAE. I would never go back to DIY. I do not worry about any CO2 related problems anymore provided a good diffuser or reactor is being used. If money is an issue I would save my pennies. If that sticky mess gets into your aquarium you will be sorry. Carbon filters should be inline before aquarium to help clean out unwanted yeast from getting in the tank. Most of the time even if no leaks are present the system will produce too much gas or not enough. The money you spend on yeast & sugar is more than the money spend on your yearly Co2 gas!