Hi,
Dont buy the welder off ebay as per the link it's a 3 phase machine...I agreee with gareth though buy a quality welder.....
You can obtain (argosheild) the gas from any boc agent but you will have to pay rental on the bottle....this is the cheaper way...with a lot of welding you'll soon go through the small canisters...I have a large bottle which we only have filled every 6 months or so....15 kg rolls of wire do work out cheaper but we tend to just use 5 kg rolls from Partco....
Don't use the impregnated wire always use a sheilded weld you get less spatter and a cleaner weld...
Happy welding
Regards
Ian