I have an 800 number in home, is there any way to tell which number is being called?

My eight hundred number is on my second line, but I also have a regular phone number on the line. Is there any way to tell if the caller is using my regular number or 800 number.

I know there is a service I can buy through the company, but I was looking for more of a one time buy. I didn't know if there was a light or something I could hook up to it that would only light if it was that number.

Thanks so much