I would get this instead:
http://cgi.ebay.com/Milwaukee-MA957-...QQcmdZViewItem.
You don't need a pH monitor...its just an extra expense.
You will still need a brass check valve, like this:
http://www.bestaquariumregulator.com/CO2.html#check. ($13.50 shipped)
Then all you'll need is some way to get the co2 into the tank. A cheap option is to use a powerhead. I like Maxi-jets:
http://www.drsfostersmith.com/produc...09&pcatid=4609.
It does suck that you have to get everything from different places, but that puts you at about $140 or a little under. And if you happen to have a powerhead laying around...that will save you about $25. Not bad. Then all you need is the tank.
If you go this route, you can definitely get it all under $200. That will depend on how much the co2 tank costs (think about $50-100)...so it will be close, but probably still under $200.
I don't know anything about the red sea setups. If they use paintball tanks, then I'd say this is a better way to go. You have more co2 and won't have to refill as often (refill=$$). The money you save by buying the red sea system will probably be paid out in refills....