I found this link on Youtube.
http://www.youtube.com/results?search_query=Archery+homemade+lighted+nock

Its a real aesy wat to make your own lighted nocks for about $3.50 a piece. I just made my first one and it works great. I bought the bobber and light at my local bait shop for $7 but I found just the replacement lights online for $3.49.