Arc welder purchase.

[m_c]

I'd recommend getting an inverter, as they make arc welding alot easier.

I've got a small Cebora unit I picked up of ebay several years ago, primarily for TIG, however it now spends most of it's time doing Arc work.
Only issue is, as Web Goblin says, is they are expensive to repair should they go wrong, so I'd suggest a new one with warranty.

As for Clarke bashing, my big MIG welder is clarke, and it's never had any issues other than the woefully undersized torch supplied with it, but that was easily fixed with a new torch. Price wise, the Clarke was the cheapest at the time, can handle 1/2" plate, and it's never given me any troubles, however it is one of their industrial range.
I've used some of their smaller stuff, and it's just as good as any other cheap chinese stuff, but at least Clarke has pretty good parts back-up.