If you are just wanting a very basic machine, either of the inexpensive machines that they have a Walmart will work just fine. At one point a number of years agoI was having problems with any machine I got not lasting very long so I decided that if it was only going to last a short time, then I might as well just get a cheap one. And lo and behold, it lasted longer than the more expensive ones I had gotten previously (never had a really expensive one, but not the super cheap one before).
I've been very happy with the Brother I got on sale for $69 or $79 several years ago. Don't remember the exact model # and I have now passed it on to a friend who did not have a machine. I had it for 3 or 4 years and used it all the time till I got my featherweight, which I'm not letting go! Now that is the perfect straight stitch machine, but not necessarily easy to find one that is cheap that doesn't need any work done on it. If I get another machine now it will be one that has embroidery so I can make labels (maybe).