I can say from experience that the first 5mm blue LEDs commercially available were about 30 UK pounds each - I was working in electronics R&D at the time and no-one was giving away samples.
I just came here to add - if you like this topic you'll love the documentary on Noyce, Shockley, and the rest of the silicon valley pioneers: <a href="http://www.pbs.org/wgbh/americanexperience/films/silicon/" rel="nofollow">http://www.pbs.org/wgbh/americanexperience/films/silicon/</a>