Ed:
Both Craigslist and ebay are good places to start, as well as any local classified listings you might have, but you'll have to be patient - these kits don't pop up all that often. On here, we maybe see one or two per year and someone usually jumps on them pretty quickly. Prices for a never-been-built kit with a roller chassis (pan) are usually between $3K and $6K, depending on what's included. Please be aware that the biggest reason why these kits never got built was that the buyer finally realized how much work was involved and it became daunting to them. You also don't save a whole lot on completing the kit (it usually costs $14K-$16K to finish one nicely) BUT, you do spread the money spending out over time so it hurts less as you go along. How long it takes is entirely up to how much time you can devote to it. If you put in 10 hours per week, it should take you between one and two years to complete it.
As an alternative to getting a non-started kit, you might continue to save your money and watch for a used VS or CMC that needs work. We've seen some on here for under $10K that would allow you and your son to actually do something fun to get it street-ready and see more immediate results, maybe getting it on the road for the following driving season, rather than several years out and it might be a little cheaper going that way than finding an un-started kit and slogging through the build.
I'm sure others on here have their opinions so listen to all sides, be patient and watch those classifieds. You might also look on the Samba and the Shop Talk Forums, as well as Hemmings Motor News classifieds (all on line) where you can set up email alerts for what you're looking for.
Gordon
The Speedstah Guy from Massachusetts
