If you really want a TIG, keep an eye out on ebay for bargains.

I bought a Kemppi Kempotig AC/DC 250A for £250 last year. Its a big water cooled machine that was set up for 3 phase but easily converted to single phase. It came with more than £250 worth of welding rods and regulator.

Think a Mig would do for most RW applications unless you want to weld aluminium.