As an example, most  new sofas around $1,000.00 are built with plywood, wafer board, particle board, or pine with 3/4" stock.  Joinery involves a dowel, if you're lucky, with a spot of glue and staples.

Average quality, starts around $2,000.00.  These sofas are built with slighty denser woods, thicker stock, double doweled, stapled but with screwed corner blocks.

Best quality, starts around $3,000.00 to $4,000.  Built with dense woods like hard maple, oak, hickory, etc.  Joinery is doweled and tightly fitted with plenty of glue, and the frame is reinforced with screws and corner blocks.  Many older sofas built before the 80's were built to these standards even though the manufacturers were considered average and the pricing was inexpensive.

Our price for reupholstering a sofa is around $700.00, which does not include new foam or fabric.  Most sofas need around 18 yards of fabric and the average cost of good quality upholstery fabric is around $30.00 to $60.00 per yard.  Therefore, the minimum cost for upholstering a sofa can run anywhere from $1,000.00 to $2,000.00 depending on fabrics and the necessity for new stuffing materials.