I was using a large folding table when I first set up my room, but the vibration from the table was so bad that I could hardly sew. I tried a vintage sewing table for a bit, but it was awkward so now we're in the process of piecing together a desk. I bought a kitchen table top in the as-is section at IKEA, and will be going back to buy two sets of cubby's to use as supports. For now I have the table top just sitting on top of the folding table and it's already a huge improvement. I have a smaller folding table that comes out into the room (on my left side) making an L shaped desk and I really like it. I took the drawer set that supported one side of my vintage table and used that under the table it's nice to have drawers right there. I went to IKEA looking for something sturdy and while we probably looked like a couple of crazies, I would sit at the desk or table and my husband would pound on the top so I could feel the vibration
Whatever you find, just watch out for vibration. Finding a really solid top seems to be important. Do you have IKEA near you? One material we considered were their butcher block counters but the table top I found was a steal. Have you checked craigslist for something used that might fit your needs? Also have you heard of Ana White? She has a ton of furniture plans in case you decide to still go that route.