The easy answer Ryan, is it depends on which one you get.
I have an M211 which is very similar to the 180. I think they only draw about 25 amps full load.
Many people will run a #10 copper wire on a 30 amp breaker. I legally can't recommend that however, a M180 probably won't burn the house down set up like that either.
For my 211 I ran #8 copper and protected it at 40 amps (I just "happened" to have a nice length of 8/2 nm laying around
You're not going to find that at your local Lowes).
The problem with welders is for convenience sake they come wired with a 50 amp plug. You can only put that plug into a 50 amp receptacle. The next guy that comes along, might just say " Gee! big wire, big outlet, big plug, that should work..." Could be a big problem.
Remember 1) the size of the load determines the size of the breaker. 2) The size of the breaker determines the size of the wire.
The real answer is because it's considered a "feeder" an Electrical Inspector would say the breaker needs be sized to the receptacle. The receptacle to the plug it fits, and the wire to the breaker. so that would mean #6 copper* wire and a 50 amp breaker.
* You can use #6 aluminum but I would stay away from that, it can easily be a hazard if installed incorrectly.
You'll be very happy with a M180