Do you have a Senior Discount day?

Yes

Yes. Senior Citizen Discount Day: All seniors 55 years of age and older receive a 5% discount on Thursdays

I believe most of them are 5% on Thursday. But that day/amount could be different per store.

At the Peony Park store in Omaha, a sign posted at the check stands says that Wednesday is the discount day, at least for that store.