I agree that basic is the best, although my basic machine is an all mechanical bernina that I paid $700.00 for.
My suggestion is to look into older model sewing machines. Look on craigslist or your local classified ads. Try to find an older, all or mostly metal model. Singer was great when they were metal, not so much anymore. You couldn't pay me to take one. Same with Kenmore. When they were metal they were good, now that they're plastic, they aren't.
Second hand also gives you opportunities to find great deals on some of the higher end machines like Viking, Pfaff, or Bernina (although if you do find an older metal singer, you're doing really well).
Something else to look for is stitch variety. You want your machine to do buttonholes of course. Outside of that, you pretty much just need a straight stitch and a zig-zag with adjustable length and width. No need for 24 different types of stitches. You'll never use them. I don't and I'm a professional costumer.
I would also point out that unless you have an industrial machine, finding thread, needles, and bulbs shouldn't be a problem. Only certain machines like Singer use specialized needles that only work in that model. Many of them use the universal needles. You won;t have a problem finding either. As for thread, it's pretty much interchangeable.
If you do go second hand, remember that it would be a good idea to take it in for servicing immediately after purchase. Just for preventative maintenance.
Of course, not to knock Fetthunter's machine or anything. If you don't sew heavily, and don't plan to, these are fine alternatives and some models are probably better than others (the newer singer I had was junk). The Cheapo Brothers are highly recommended for a knockaround machine in professional circles.