You can name more than a single item for the same price as one

Steps to reproduce:
1. Place an Anvil and open it's interface.
2. Grab a stack of any kind of stackable item and put it in the first slot
3. Name the item whatever you want.

If you did it correct, you named 64 items for the same price of one item. (Currently 1 level for starting price as of 14w11b) This should have been 64 levels to name your stack.