Here's my suggestion to Zackey's as a new business that wants to build the business.
How about a hand lettered, very plain sign in the window that says:
Pizza slices - One Dollar - all day
It will get new people into the restaurant for a try and a look-see.
If McDonald' can sell a double cheeseburger that is pretty good for a dollar, then why not a one dollar slice?
Inquiring stomachs want to know?
