How much will it cost to build a kayak?

Most of the cost of building a kayak is labor, but doing the work is part of the fun so we won't count that here. Some people are really good at scrounging up materials or have especially good access to quality stuff cheap so we won't count that either, but is worth looking you around for unexpected sources of materials. For example old telephone poles were often cedar...

A strip-built kayak needs about 2 board feet of wood for each foot of boat length. Obviously longer boat and wider boats will need more and short boats will use less, but this lumber will generally cost $150 to $200. Forms for a stripper can be cut out of one sheet of inexpensive plywood or MDF and mounted on a simple 2x4 or plywood box beam for $50-$150.

A stitch and glue boat will typically use several sheets of high quality marine grade Occume plywood which can be quite expensive per sheet. A typical boat will take $180 to $250 worth of plywood.

Fiberglass and epoxy costs for either method is about the same. Figure on about 4 times the length of the boat in fiberglass for a typical kayak this runs about $150 to $200. A kayak will also use about 1.5 to 2 gallons of epoxy resin that can run from $100 to $200.

You will also need various sundries and expendable like sandpaper, brushes etc. which you can figure on paying around $100 for.

In summary:

Stitch and Glue
$150 - 200