You got it Eddie! That phone number appeared on TV (mostly cable) from the late 70s until around 2000. It was apparently the phone number for Turner Broadcasting. While it was common with music, other products and services such as life insurance used that number as well. It wasn't uncommon to see that phone number in more than one commercial on the same commercial block.
There was a promo for an "affordable" jewelry set, where for one low price you would get enough pieces to fill a jewelry box. Of course the last plug went something like - "call now and we'll throw in this beautiful decorator jewelry case for free".
So many different ads for so many different products but I never noticed that the number was the same for all of them. Makes me wonder if the promos for Slim Whitman back in the 70's was using the same phone number for ordering.