There are many people quilting on sewing machines from Wal-mart that fall in your price range. My machine that I use for decorative stitches is a cheap Brother from Wal-mart. Until recently it was my ONLY machine and I was able to quilt large throws on it it.
Buy the best machine you can find that falls in your price range. Look at Wal-mart, look at dealers and do some research on the machines you find available. You can find many customer reviews online and get a feel for what people who own the machines are saying about them. Most of all don't let anyone push you into buying a machine that costs more than you are comfortable paying.
I don't do machine embroidery, so I can't answer that part of your question.