Aug. 22 1979 Pillow Talk Rotary Phone

I have an old phone my grandmother gave me that still has the manufacturer sticker on the bottom. The information says: Model- Pillow talk, Date- 22 aug. 1979 and is guaranteed by onyx telecommunications ltd. there is other information like model number and registration number on the sticker as well. In the center of the rotating dial there is a head shot of a womans profile. I was wondering if anybody knew how much it might be worth or any other information about this type of phone would also be helpful.