Electrical Help Needed

[machinistmn]

I am planning to put a surface grinder and a bridgeport in my garage, and then eventually a CNC. I have to run 220 single phase to my garage. I have been reading a lot of forums about RPC's and VFD's. But I have a few questions. The first is does anybody know how many amps a G&L 370 (12 x 24) pulls, and also a bridgeport (9 x 42) (ballpark guess)? I have 100 amp service to my house, and I don't know if this is enough. All appliances are natural gas. We do have central air. The second question is which is better, a VFD or RPC? The third is I talked to a guy about 220 wire, and he told me he had 220, direct trench, 12 conductor wire that he would sell me for $3 / ft. Is this a good price, and is that too beefy for what I am doing. I'm trying to go the least expensive route without cutting corners. All advice will be appreciated, and I love reading these forums! Very informative.