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)
Here's how to minimize and delay the chunk that Uncle Sam claims.