I don't have a big collection but my non-Cannondales are a 1994 Mountain Cycle San Andreas which I only acquired recently (Dec. 2019) and my own titanium road bike which I made when I attended the United Bicycle Institute's frame building program in Ashland, Oregon, back in 2017. I made the road bike because I had a NOS vintage Shimano 600 Arabesque groupset that was given to me by my uncle as a gift when I moved out west. He got it as payment for a side job he did back in the '70s and never used it! It sat in his garage for 20 years, all in their original boxes. I took it with me when I moved and it sat in my garage for 20years! I came across it in 2017 on a big clean-up and thought enough is enough, I gotta build a bike to use it with:
The class admission cost includes the materials to build the frame - which you keep. All in was $3K. A little more than a 1/3 of that cost covers the materials and that includes tubing and all pre-machined parts from Paragon Machine Works (head tube, BB shell, drop outs, cable stops and whatever else you want to weld onto your frame). Cost is the same whether you build a BMX frame or Mountain/Gravel/Road bike.