Yes there are and they are less than $200 for a full setup, these are the wire fed type you can get at a Harbor Freight.
The power supply is the trickiest part, but the low end welders only need a 20amp circuit, which is a typical power level that might serve a suburban bedroom. You would need a vehicle but even a couple of deep cycle lead-acid batteries and an converter/inverter would power several minutes of welding, more than enough as typical spot welds only require ~10 seconds of arc time.
Source: am farmer and recently built a 9 foot tall wind driven kinetic sculpture of a Wendigo out of scrap rebar found about the place.