Vudu has The Purge: 4-Movie Collection (Digital 4K UHD) on sale for $17.99.
Note be sure to select the ‘UHD’ option. All films are Movies Anywhere (MA) compatible
Includes
The Purge (2013)
The Purge: Anarchy (2014)
The Purge: Election Year (2016)
The First Purge (2018)