Here is a cheap one.
http://www.harborfreight.com/cpi/cta...emnumber=94056
There is a cheaper one yet, but this one has 2 amp settings. You would want that.
Spend another $20 and get this one if you have a TSC nearby. This will weld most anything the average homeowner will work on. Easy to use after alittle practice.
http://www.tractorsupply.com/webapp/wcs/stores/servlet/ProductDisplay_10551_10001_49007_-1______14151|14220|14238|49007?listingPage=true&Sp ecial=false