I have a Handi quilter 16 on a frame. I think if I were purchasing again, I would go the 18" I do like my 16 and will not be upgrading. My son made the frame for under 150.00 with storage shelves under.
My two friends just purchased the Sunshine 16. I tested it with them at the Grand Rapids AQS show and liked it. they both got the sit down model. It is a very basic machine without all the bells and whistles and would still be in your price range. Both plan on only doing their own quilts and charity quilts and I think they made a good choice. The only drawback is it took 4 months to get it. Sunshine 16 builds the machines as they are ordered, no packed warehouse ready to ship.
You should check on used machines if you want a name brand and stay in your price range. My machine was used and I am happy with my purchase.