That is about Ｔｈｅ standard price for a Milwaukee MA957. I would, however, recommend a different regulator build (i.e. the ones that GLA, Sumo or Rex Grigg). The stock needle valve on the MA957 is not the best, and will require adjustments on a regular basis to achieve a steady CO2 rate.
Thanks for the tip! I'm looking for a great regulator for a good price. I found a Victor vts250a dual guage for 50 bucks but found it that it's only for air. I checked out the ones you recommended but they're pretty expensive!
I believe the VTS250A is a dual stage regulator that can be converted for our purposes. You will have to remove the CGA580 fitting and simply put on a CGA320 fitting instead.
Don't forget that if you are only buying the regulator, you will need the other parts too (solenoid and bubble counter are more optional, but you will definitely need a needle valve).
While the prices from GLA, Sumo and Rex Grigg may seem a little steep, you mustn't forget that they include labour costs as well. You can easily look for the individual parts yourself, and it would likely be cheaper, however. Of course, this means that you will have to do some homework on the parts.
All gas regulators are equal, as far as being used on different gases is concerned. They differ in how high an inlet pressure they are good for, and most are good for over 2000 psi, and they differ in what range of low pressures can be regulated, with our CO2 regulators needing to be good for the 10-30 psi range, which means a regulator that only goes up to 200 psi max, with 100 psi being much better. The gas the regulator can be used on is set by the inlet fitting, which connects to the gas bottle, with CO2 regulators needing a CGA320 fitting to fit CO2 bottles. Those inlet fittings just screw into the regulator body, so they are easy to change when you want to change the gas the regulator is to be used for. So, any regulator good for 1000 psi or higher inlet pressure, and with a 200 psi or lower outlet pressure, will work for CO2. A few regulators are made for 4000+ psi, but you don't see many, and those aren't suitable for our use, unless you replace the inlet gage so you can see the 800 psi or so that we are trying to measure. Those would very likely have a 400+ psi outlet pressure too, also not good for our use.