When the store is having an item with discounted price, I say it's "on special".
"Sweetheart, check to see which ice cream is on special, and get that one. Unless it's Friendly's ice cream, because that's nasty, so then just get the store brand."
"I bought six boxes of herb tea because they were on special, and it's not like they're going to spoil."
My son tells me that "on special" isn't right, you're supposed to say "on sale".
By you, do you hear "on special", or is another New York thing, like waiting "on line" at the bank, waiting for the next available teller?