I think I'm pretty close to pressurised with my diy system. My 2 1 gal gas cans sit in a heated water bath, homemade needle valve. So I can control how much co2 I'm dumping in. I spent $5 on a jar of yeast about 6 mos ago and a 4 lb bag of suger is $2, I use 2 cups suger a week, not sure how many cups in a 4 lb bag. Say that 4 lb bag lasts 6 weeks, thats $8 every 6mo for suger and $5 for yeast which is $14 If I did my math correctly. Yes with pressurized you can set it and don't have to mess with it daily making sure the bubble count is pretty close. I have kool-aid in the house to so the suger is already in the cubard. The town i live in the place that fills co2 tanks wants $20 so I'd only be saving $10-$15 year. As messing with the co2 all the time I've just gotten in the habit of checking the bubble counter when walking by or lokking at the fish which I look at for at least an hr a day.