VUDU offers downloads of a selection of horror titles in HDX for 99 cents each, as listed below. That's less than what it charges for rentals. (This page offers a good primer on the differences between HD and Vudu's HDX.) The deals:

Return of the Living Dead: Part 2 for 99 cents (pictured, low by $8)

Freddy's Dead: The Final Nightmare for 99 cents (low by $7)

Wes Craven's New Nightmare for 99 cents (low by $7)

Lost Souls for 99 cents (low by $8)

Trog for 99 cents (low by $8)