I have also had great luck with the very low end Brother from Walmart. For awhile I was finding that no matter what machine I got, it didn't last very long, so I figured if it was going to quit in a year or two, might as well get the cheapest one. Then I discovered that it was actually a really nice machine, did everything I needed it to do and has lasted me over three years and has now been passed on to a friend who did not have a machine. Still working great!
Of course if you could find her a featherweight or other similar vintage machine at a good price....