Week 2 of DC's huge sale is on, ending 6/15/15. Remember that DC books are available in the separate DC app where one could buy discounted iTunes cards for some savings versus Comixology proper.
It includes 345 books from the 1980s to 2015 at up to 75% savings.
https://www.comixology.com/DC-Univer...Sale/page/6957
Comixology has another weeklong sale, this one from IDW on G.I. Joe books; 2 collections and 20 singles at 50% off.
https://www.comixology.com/G-I-Joe-Sale/page/6967