[neilshieh]

I suggest you buy a 5lb co2 tank locally first. look on craigslist or your local airgas. Remember... you get what you paid for, so you might want to consider getting quality stuff in the begining rather then paying double down the road when you run into a slew of problems with cheap single stage setups. If you're only dosing 1-2 bps then i suggest you get a paintball co2 setup. you should be able to get everything for under 50-60 dollars and just pay for co2 refills every 2-4 months. the benefits of a 5 or larger tank would be one 10-20 dollar refill would last you 1-2 years depending on how much co2 you are dosing. the refills for paintball co2 start to add up over time, so you may want to take that into consideration. If you're interested in some dual stage regs, i have some. though shop around with other hobbyists on here and theplantedtank and find a deal you like.