This is a link about what size table you should consider. It's one person's opinion, but she makes a lot of sense and speaks from experience. As a new free motion quilter, I enjoyed all 4 of her YouTube videos. So watch the whole series if that interests you. This is the forth video in the series. She starts talking about the table in detail about the 8 minute, 10 second mark - if you just want to get to the point.
https://www.youtube.com/watch?v=-DmW-1L9Ua0
Sometimes my memory isn't perfect, but this time, I remembered correctly. While I haven't done business with this place before, this is the best price that I found on a Sew Steady table: $40 for an 18 X 24" table.
http://www.voguefabricsstore.com/Sewing-Machine-Extension-Table-18-x-24.html