I wouldn't buy a new Singer in that price range. Not sure about currently, but I know that non-vintage low-end Singers have a really bad rep for reliability, tension, etc.
A lot of people really like Janome for a take-to-class machine. They also weigh in at about 12 lbs. Here's a link to one in the Gem line:
http://www.amazon.com/Janome-Jem-Gol...dp/B000FLH2VE/