Is this something you plan to do on a regular basis? If not, it probably isn't worth the hassle.
And it depends upon the bank and best to ask. Worse case they require you to get an account. Just open one and put in the minimum amount. And then you can deposit the halves into your account. They would give you less of a hassle that way.
But first, make sure they can order halves for you.
It might even be better to have accounts at 2 different banks. One for buying them and one for returning them, so you get new ones each time.