The minimum 17 CFM @90 psi that this system uses is going to require a fairly decent air compressor. An air compressor rated at 20 CFM @ 90 psi is going to run $400 to $1,000 to buy. You will also have to buy the 150 to 200 feet of 3/8 air hose to go with for another $100 to $150 for "cheaper" air hoses. You will also need a supply of power for this because the air compressor will pull a steady 20 amps or more. Count on $50 to $70 for every 50 feet of cord you have to run to get power to your compressor on site.
The biggest thing to keep in mind is that most compressors are not designed to run full out non stop for hours on end, they tend to burn out fairly quickly. I would advise a commercial duty compressor if you intend to buy one and expect to be in the area of $1,000 cost when you buy it.
If it were me I would spend the money to rent a tow behind air compressor that runs off a gasoline engine. You will also be able to rent the hoses you will need along with it.
This system works well in topsoil and sand but when you get into clay or rock they warn that you will slow down considerably. In clay they say it will cut anywhere from 3 inches to five feet an hour. In rock they say to expect around 1 inch an hour.
If you had to drill our well with that you would have 30 feet of clay followed by 120 feet of granite. So a drilling rate of 3 inches to 5 feet an hour for the first 30 feet. So anywhere from 6 to 120 hours for the first thirty feet.
The granite drilling at 1 inch an hour would take 12 hours per foot for 120 feet or approximately 1,440 hours to drill. The grand total drilling time of between 1,446 to 1,560 hours of drilling time. Now with my well as an example this would give you a flow rate of 50 gallons per minute and a reserve of around 10,000 gallons. To put that time into perspective you are looking at drilling 8 hours a day for 180 days to drill my well with that system. I do believe this is all rated on the minimum 17 CFM @ 90 psi, if you run a better compressor and get more CFM you are likely to drill at a faster rate of speed.
But keep in mind, my neighbor next door just drilled three wells in a week literally 1,800 feet from my well and didn't hit water once and each well was dug to 250 feet. But in that small distance the under laying stone goes from granite to fractured basalt and apparently the water does not penetrate the basalt like it does the granite under me. If you had drilled my neighbors wells to 150 feet each you would have spent 540 days drilling to get no working well. I think that I can guarantee that at 1,400 hours of full tilt air on a compressor you are going to burn out at least one or three store bought compressors digging your well.
I would go to the local courthouse and see what wells around your property are for depth and take a look at what the driller said for what they drilled through be it clay stone etc.
Here is a Youtube video from this company on drilling a well with this unit...
I have never tried to "drill" a well before, I have dug a number of surface wells though. On my last farm I hand dug 4 surface wells in different areas to pump livestock water from. I dug them all 6 foot by 6 foot square and to a depth of 16 to 20 feet deep and I had a great supply of water in all of them. Each year I would wait until late summer early fall and pump out all the water I could and dig them a bit deeper increasing the amount of water reservoir I had in the wells.
I am trying not to rain any parades or anything, but I thought you should have a good understanding of what you might be undertaking with this project.