I love sewing, how exciting that you are looking for a new machine!!
If possible, I would avoid buying one from Walmart. I have heard lots of people have problems with them. They might save a little up front, but in the long run they could cause more frustrations and aggravations than its worth. On the other hand, if that's the only option you have, it might be worth it. I know at least one person who is satisfied having gone that route!
You have been given some great advice here! I wanted to add a little something to think about. You mentioned you are interested in quilting, and because of that I recommend testing any machine you are considering with a couple of pieces of fabric (cotton or flannel of the type you will be using, and a piece of batting in between) to see how the machine sews quilts. Of course, if you'll be hand quilting, and just piecing the top by machine, that won't be an issue.
Actually what I was going to say before I side-tracked myself, lol, is to look for a machine with an excellent straight stitch. I have 4 machines (not including my sergers
) and the most expensive one, a Janome (that I love, don't get me wrong!) has the worst stitch quality of all. My cheapest (it was under $300, with everything you could want, really, including a walking foot for quilting and the 1/4" foot for piecing) has an absolutely perfect stitch. It's a Craftmaster 4700 (I think its a lower-priced Janome in disguise, lol) and I LOVE this machine. I think it's the perfect beginner machine. It's easy to use, and has plenty of useful feet and features so that you won't ever really outgrow it. Unless you decide you need a bunch of fancy stitches, it should be good for years of great sewing time.
My other good stitchers (machines!) are older than me. One is a Singer Featherweight (inherited from my grandmother) and the other is a Bernina Record made in about 1961-I found it at a thrift store for $35.
Good luck, I hope you let us know what you decide!
Oh! And if you need more advice, try this:
Lots of Sewing machine reviews here!