I have about 8 sets of the old C9 light strings that I bought from some factory on Motor Parkway, in Hauppauge, 23 years ago.  Believe me, they don’t owe me anything after all this time.  Every once in a while I had to buy replacement bulbs from Pergament (remember that place) or ACE Hardware and then eventually, Lowe’s and The Home Depot.  This year, no one is carrying the old fashioned painted bulbs.  I guess if I looked on Amazon I could find them.  The Home Depot has a clear, colored glass version in different colors for $2.98 for 8.  Considering a box of 4 used to be $9.99 I guess I’ll have to go with those.