Without a picture it is difficult to know what you have. However, I have a set of Christmas lights that has a transformer with a button switch. Depending on how many times the button is pushed the lights will play Christmas music with lights staying solid, with lights blinking in time to the music, no music with lights solid, no music with lights blinking. There is no on/off switch. If you hit the button once, you have to keep pushing it to get the music to stop. It is quite loud (and borderline annoying). I’m not sure of the manufacturer but mine is a set that Avon sold in the mid 1970’s and (as I remember) was discontinued by the end of the 80’s. Perhaps yours might be the same kind of thing. I have no idea what they would be worth though.