I'll second the
www.cyberweld.com recommendation, I've bought several things through them, great service, better pricing than most.
As for the plasma itself, I would like to offer some more generalized advice:
1) don't buy the plasma you need now, buy the most plasma you can reasonably afford with an eye on what you will be doing in the future. give yourself some headroom to grow/work on thicker stuff.
2) Buy a name brand. Most major companies are pretty good, miller/hobart, esab, hypertherm, etc.
3) Consumables -- check your local shops, buy the plasma you can easily get consumables for and/or local support. Nothing ***** worse than being stuck with having to mailorder everything when you need ONE part.
Now saying all that, I have a Thermal Dynamics Cutmaster 101 (way overkill for you), I particularly like their One-Gun design. All their cutters use the SAME gun (and consumables will interchange). That gun/lead can also be removed from the machine making storage nicer/eacier. I've never needed it, but you can also add additional length to the whip by buying extension leads. None of these features apply to other brands.