What is your budget for a compressor? Plan to spend twice that when it's all said and done.
If you need a home compressor, do you also need to maintain your own cylinders? Add in the cost of training, tools and supplies for that.
Are you going to be mixing Nitrox? Add in the cost of analyzers, oxygen, cleaning, etc.
How are you going to verify the quality of your breathing gas? How are your going to check for carbon monoxide? IF you are going to use a gas-powered portable compressor, you've got to check every cylinder for carbon monoxide. How many filters will you use? Do you have a gas lab picked out yet?
I have an Alkin W31. It is among the cheapest of the smaller compressors at about $3,000. Works great. Also runs at a relatively slow RPM. The US distribitor of Alkin, in the other hand, not so great.......):
As far as continous blending is concerned, are there any small compressors in the USA that are approved for blending up to 40%? It's common practice to do CB, but do any manufacturers actually advertise that their compressor is approved for CB up to 40%?
I have been blending Nitrox with my Alkin W31 for over a year now without any issues. I change the oil more frequently than recommended and check each cylinder for carbon monoxide. So far there have been no issues.
The Alkin advertises that their compressor is approved for continuous duty. I never run mine for more than 60 minutes at a time, but do regularly crank my storage bank up to 4,400 PSI.
Good luck!