This isn’t exactly a deal, but I have not seen other posts about it yet. The Batman CMF series 2 is out at WalMart.
http://jaysbrickblog.com/2017/12/06/lego-batman-movie-minifigures-series-2-official-photos/
I checked out a couple bags and looked at the images on the box, but did not buy anything, although I liked the Batmerch Batgirl.
https://www.bricklink.com/v2/catalog/catalogitem.page?id=160981#T=S&O={“iconly”:0}
One of the Batman CMF2 bags had a flexible headgear, and at the time I had no clue what it was, maybe it was that Batgirl. Beach Batman seems like an easy one to find, considering it has a dolphin in the bag, and its probably is a good deal to get the with the $2 dolphin, provided you also want the minifig in a Speedo.