Kits may seem pricey to the uninitiated but kits usually contain top quality components and produce boats that are in a class with the lightest production boats costing between $2000-$3000. Kit makers use BS1088 or BS6566 plywood that is often refered to a "aircraft plywood". This quality of plywood is required for home built aircraft and it isn't cheap. 4mm BS1088 is about $41 a sheet where I live.
Many home builders use $8 a sheet luan underlayment from Home Depot but it's a poor relative of BS1088 and no kit maker would dare use it for fear of getting his brains sued out.
For anyone who has never built a kayak a kit is an excellent choice. It will give you many small challenges but will remove the major hurdles. Most kit makers offer assistance in person or on the net to help their customers over the hard spots.
A typical kayak built from plans requires about 4 sheets of plywood @ $35-$45 a sheet, a gallon of epxoy resin at $55-$85 per, 50 yds.of fiberglass tape @ .80-$1.35 a yd., enough fiberglass cloth to cover the hull @ $6-$9 a yard, plus a lot of odds and ends that add additional cost. Plans cost $35-$100 but you can buy how-to books @ $15-$30 that have plans for several boats in them.
The cheap alternative are skin-on-frame kayaks. There are no kits for these so you have to figure everything out yourself. Some of the more astute builders claim they can knock out a SOF for less than $100.
Unfortunately,"Ace is not the place" for boatbuilding supplies. Stitch and Glue boat building is a cross between monocoque aircraft construction and old fashioned carpentry.
Hope this helps.
Charlie

It sounded like something fun to do building a kayak and perhaps saving some
: money. But, looking at the kits they are awefully expensive. How costly
: and more difficult is it to build your own and buy all the wood and stuff
: at a hardware store?