You could get away with just a circular saw and a router. It is reasonably straight forward to make decent rabbets with a router and with the addition of a few homemade jigs for the saw and router, you can do a lot more. If you recycle a couple of pallets into a cutting table, you can cut down big sheets of ply single handed and accurately with a power saw. This might work out cheaper than buying a table saw, not to mention a bit easier to store. Like everyone else has suggested, don't buy cheap and nasty tools, they will let you down and generally burn out at the most inopportune time (refuse to cut straight, make a lot of noise, fall apart....). I have a Makita router that takes 1/2" bits that I bought second hand years ago and it is up to what ever I can throw at it. There are a few good brands around that the builders seem to like - Dewalt, Porter Cable, Makita, Bosch maybe.
If you go the power saw (circular saw) route, and then feel the need for a tablesaw, there are some systems around that you can mount your power saw in and use like a table saw (Scheppach, Triton Work Centre). Certainly no substitute for a good table saw with a cast iron table, but serviceable for most work and you can pack them away when not needed. A good setup if you have limited space. With a few scraps of timber and some small machine screws, you could even make yourself a simple "work centre" for a power saw.
You would have trouble making rabbet joints with a band saw, especially if you have limited experience, but you could do it with two cuts on a power saw work centre (or table saw). You can also do reasonable rabbets with a sliding mitre saw (as long as it has depth of cut adjustment) and they are great for cross cutting boards. Just a few more ideas to throw in the mix.
Simon