Be wary of a sale like that. Find out the exact model of that Singer in order to get reliable recommendations. Also, once you know the model number, you can look up reviews of it at
http://www.patternreview.com (join for free in order to see old as well as new reviews).
Personally, in that price range I would probably be looking for a Janome 6600P or 6500P. The 6600P has the accu-feed system (similar to Pfaff's built-in walking foot) but might be a little out of your price range. The 6500P is almost the same machine, but without the built-in walking foot; should be within your price range.