my welding class is selling off some of their wire feed welders. i think they got a grant and are upgrading. they are selling about 16 lincoln 135 plus welders http://www.weldingmart.com/Qstore/p001647.htm they are a couple years old i believe. look to be in pretty good shape. im going to find out what the price is tomorrow and if its good i need to buy it right then since there are over 400 students/potential buyers. what would be a good price for a used one of these? whats the highest i should pay. new ones are about 540, so i figure if they want over 4 bills, then i might as well get a new one. what do you guys think?