I was looking at Menards and they have decentish kits for 10k but like you said, doesn't include labor or concrete. If I do this I'll be having Sam do the concrete.
A friend of mine at work put a 30x40 kit from Menards together but he did it himself. 15k for concrete and his kit was like 12k.
The kit from Menards includes all the wood, shingles, etc. A google search came up with some Garage journal site that said labor would be about the same as the cost of the material (12k). Then you're looking at 15k for a floor. Now you're easily at 45k for a garage. Ugh.