The Sonex plans are without a doubt the best in the industry! They are detailed, concise, and extreemely well layed out. Everything you need to build the plane is included in the details on the plans. There really is no need for a builder's manual.
After I ordered the plans ($600), I spent about 6 months reading through them. This may sound impressive, but really I had no choice as I was deployed to Iraq for Operation Iraqi Freedom. Believe me, I would have rather been home building!
The plans are very intimidating when you first open them up. There seem to be endless pages, and each page is so jam-packed with notes and details it will make your head spin. But after spending some time with them, you start to visualize the parts in your mind, and they seem to practically jump off the page at you. After a while, things really do make sense and I felt an incredible urge to jump right in (there was that whole Iraq thing though...). I have to confess though, when I first opened that box and unrolled the sheets, I could understand why there was a steady stream of "barely used" plans for sale on the internet. I can see how some people would be overwhelmed.
It is hard to show the quality of the plans in just a few pictures, but these should help illustrate what I am talking about:
The Sonex is constructed from basic materials, namely 0.025" and 0.032" 6061-T6 aluminum sheet, and various sizes of 1/8" thick 6061-T6 angle stock. Although I'm using the full kit, the low materials cost makes the plane a pretty attractive and inexpensive plans building project. All the raw materials to build the plane can be purchased for around $1800. The exact price really depends on where you purchase the materials. Buying from local sources can be the best solution, as you avoid the shipping costs for a 12' x 4' crate. Prices vary, so shopping around may save you some money. I found a local source that quoted me $42 a sheet for 0.025" and $60 for 0.032" sheet. This is about 1/3 less than the mail order houses charge, even without shipping.