Rogers & Bro - Triple Plate - Baby's Cup - Pre 1900

I found this cup for a dollar at a yard-sale. I intend to resell it, but I have no idea of its value. It appears to be older than a lot of the other Rogers & Bro holloware items that I have come across in my google searches. Not sure if that is just because of the tarnish of the warped rim. Could anyone tell me more about it?