When's a Large a Small

A burger joint in our area had a deal for fries.  They are selling small, medium, or large for $1.00.  I had a taste for them.  I stopped by.  I ordered a large.  They normally charge $2.59.  We used to buy large and share.  I opened the bag.  What I saw was a taste.  I would not be able to share those fries.  Their commercial got me in the door.  I won't be going back.