That's a hard question because there are so many different brands w/ different options. I started out w/ a machine from Wal-mart. I bought it 20 years ago with my first paycheck. It cost $89 and I had NO clue how to use it.
Since then, I have purchased 4 more machines. Some were less than $200 and one cost more than my first car. I'd try to determine what was absolutely necessary for you to be happy completing a quilt. Then, I would set a buget. Try out machines and don't be hesitant to look at used ones too. I'd try to get the most for my $$.