What are my glass slot Machine plates worth?

they are from the bally manufacturing corporation in chicago. the date on it says 9.14.78 and it looks old fashion i also have glass plates that have the bally manufacturing name printed on the front with a border of yellow/gold frill.i have10 of the slot machine plates and 9 of the bally Continental plates. i found a few scraps of news paper from wed.july 15 1981 wedged in Between the plates to keep the heavy Glass plates from sticking it did a good job because these are all like in perfect condition.