I say if one is considering purchasing a new sewing machine, ask yourself for what type of projects and jobs that you will be mainly doing with the machine. Is it just straight stitch sewing with a little bit of zigzag? Will you really be using any of the decorative stitching, and if so how often? Buttonholes, although Singer's buttonholer attachment is the best in my opinion.
If you are just going to use straight stitch then I would look for a vintage Singer with motor (I'm one of the few nuts that likes to treadle), for example: Singer 15-90/91, 201.
And if you want zigzag with some decorative stitches then Singer 401a, 500a or even the Singer 328.
You could also go with a Necchi Supernova, but why I suggest the Singers over the Necchi is because of parts.
Most likely you will never have to worry about a part if your machine is in great shape, but there is always the what if or if it does break. Singer parts are easy to find, just find another cheap machine that has the part.
All can be found cheap on CLs or garage sales, just have to keep an eye out for the deals.