CO2 question

Just purchased almost everything for a paintball tank setup. I am searching for a diffuser right now. The system will be on 24/7. I'm only going to have about 1-2 bps. Is there any one particular diffuser I should be looking at? Ebay has some (1-20gallon for $1, then I think the next one is for around 55 gallons for $10). I realize that the diffuser and drop checker are fairly simple items, but as far as quality goes, who should I trust?