(imho) That all depends on your required "duty cycle", if it just going to run for a few hours once a week, or is it everyday for eight hours... So, if you have a high duty cycle you should look at the ADJ Products BUBBLETRON(about $100), and if your duty cycle is fairly low, then maybe the Zerhunt Automatic Bubble Maker(about $40). When I looked into this before I found the biggest issue to be cost of the bubble fluid, however you can make it yourself (in the US you can buy the "raw" glycerin) .