Depending on the joint configuration, you may also consider silver solder or sil-phos on the stainless. It is not as strong, of course, as welding..... but is easier to learn and can be buffed out to look decent. It's not a color match, but if this is a non-cosmetic joint, it may serve nicely.
Lowe's, for example, has a small oxy-Acetylene portable gas rig like you might see A/C guys carry.
http://www.lowes.com/pd_98353-1703-...rentURL=?Ns=p_product_avg_rating|1&facetInfo=
Pretty handy, easily portable.
Lots of opinions on welding, nearly as many as there are methods and materials that dictate the best approach. There usually are more than one way to accomplish a job, so you must be the one to choose what the majority of the welding you are intending to do, and try to decide what type of equipment would suit your purpose, both immediate and longer term. Many times you can start with something basic, like an oxy-fuel set that will allow cutting, welding, and brazing and silver soldering in addition to general purpose heating, which is handy for countless tasks and not something that most of the other methods and equipment can do.
I can go along with MIG being about the closest to a general purpose machine, and with the proper selection of shielding gases and wire can weld the most common materials easily. Heavier materials can be welded with a MIG, but of course along with heavy capacity comes larger, more expensive machines. But that doesn't mean you can't be patient and get a good used machine from someone.
TIG is a more technical method, and also the most versatile is you consider the range of different materials that can be joined with that process. But again, it is not easy to learn (but hardly impossible) and far more "fussy" to achieve good quality welds. My own preference is TIG for small, light, precision welds that must be high quality. Also you can weld dissimilar materials with TIG, which is difficult to impossible with some other methods. And materials that you normally wouldn't even think of arc welding.
For heavy duty, rough work, as several of the guys have mentioned, good old fashioned "stick" or rod machines are in their niche. There's a reason they are the machine of choice for most pipeline, outdoor, and large tank/vessel work. But again, capacity comes with cost. Ac only machines are cheaper, but there are some rods you shouldn't use with them, and some materials that, for all practical purposes cannot be properly joined with that type machine. AC/DC machines cost more, but expand the capability, not necessarily in material thickness, but in types of rod that can be used, which gives more latitude in position and base material weldability.
Of course, it would be nice to have all the different methods, including E-Beam and Laser equipment, but that's not realistic for a home shop. So consider where you want to start, learn that method well and then decide which way and how far to expand your welding capability.
)
