I work in construction here in Ras Laffan, in the LNG plants. I have been involved in fabrication of piping for over 11 years now. The two methods of manual welding we use are TIG and stick (or SMAW). I can tell you that In terms of visual appearance, nothing beats a TIG weld. If the welder is good enough, the results can be absolutely stunning. The appearance of the finished weld is as good as the automatic machines that we also use.

SMAW is the most common and I think that the welding sticks are cheaper compared with the TIG rods ( I don't know exact figures because our company buys in huge quantities). Also the equipment needed is much simpler for stick. You can get a small portable electric welding machine that you can plug into standard power outlets. This would be perfect for your type of work. For TIG, you need to get involved in argon and oxygen gases and the cost will go up sharply.

Anyway these are my thoughts. Hope they help in some way.