I made this sewing table using Ana Whites Sewing table for small spaces plan. I used 3/4" fir plywood.
I did however make changes to use continuous hinges (aka piano hinges) and upgraded the legs to 2x2's. I used folding leg brackets from Lee Valley Tools found here: http://www.leevalley.com/en/hardware/page.aspx?p=40035&cat=3,41306,41309
It's finished with a dark walnut stain, and three coats of water based varathane. All told this project took about a week. I had the pieces cut for me by the lumberyard, but they still required sanding before assembly. Then assembly took another afternoon. Staining & finishing took the longest, probably 3 days, since I could only work on it in the late afternoon - evening.
$30.00 Hinges, screws, & 2x2's for legs, paint brush
$20.00 Stain & Finish (some savings here as I had some leftover from another project)
$30.00 Folding leg brackets
$50.00 Lumber Costs (this can vary wildly depending on your wood selection)