I got a Thomas Sodium Vapor duplex "safelight" and discovered it was too much light for my darkroom. Then I found a used Aristo Red safelight for very little money and love it. It uses a discharge tube and produces mono-chromatic red light--lots of truly safe light. Only available used, now.
I don't understand the deal to save a little money, but if you looked at Kodak safelight fixtures (when they were last available new) and filters, they are extremely expensive. A 5-1/2 inch round OC filter is now $54 at B&H.