yet another CO2 system Q

I am thinking about buying a CO2 system. From a catalog of a Hydroponic 
supply place, I found a CO2 system. Their system includes { regulator 
with one guage, 120V solenoid valve, flow meter, tubings }, and the price 
is $140. They sell aluminum tank separately ( $120 for 20lb ). My 
concerning is whether the flow meter will give fine enough control for 
our purpose. The flow meter has a knob for the control and a floating 
bead to show the flow rate. And is their price reasonable ? I don't care 
the reactor, since I'm going to make one according to E. Olsen's design.