Biggest problem with welding galvanized metal are the fumes in an enclosed area with no proper ventilation as the fums can make you sick or even kill you.I’d go with the 10,000.00 range. Those 4x4 cattle panels ( galvanized ) will need to be treated to accept paint. Use a good paint.....( see expensive ) or you will be repainting often. Also galvanized is a pain to weld.
And the great thing about galvanized steel is the zinc coating is for reducing corrosion. Painting is more for cosmetic purposes than actually needing for corrosion protection.