There are a few good machines out there, I chose a more expensive Miller CST280 knowing I would be using it a lot and spent $2200 without leads. Had to install the 240V plug and open the machine to swap from 480 down to 240V. Can buy a lesser machine but need to look at duty cycles, reasonably I would not expect much of a machine for less then a grand. Mine is rated 100% duty at 165 amps 240v, 180 amps 480v (3 ph), is also convertible to TIG. Anything too light may cut out too often and screw with your welds. I could burn 1/8" 7018DC rods one right after another with the slag rolling off as cooled where my old buzz box would flat cut out after three and had to wait for ten to fifteen minutes between rods to get decent welds.
If you go this route check with your steel supply as to rods, they will have access to good quality DC rods.