If you're willing to stretch into a third color, Impact Tremors is a nice cheap option for making this an infinite damage combo. Stretching into red gives access to Lightning Bolt and a potential fun time with Purphoros, God of the Forge.
Obviously, since this is a budget forum, you could help your manabase out by implementing a standard staple amid rotation, Sylvan Caryatid.
A sideboard question for those playtesting the deck. The new M15 card Return to the Ranks seems like it could have a place here for attrition match-ups. With Pack Rats, Dark Confidant, and Tidehollow Sculler being two drops respectively, being able to resurrect them late game might not be a terrible plan. Additionally, if you are playing a couple of Darkblast, this could help us recycle some of the creatures we dredged.
I know that this topic has been dead for a year now, but I am also interested in making Warped Devotion work. I've been working on a build primarily using black, but with blue for bounce.
Obviously, since this is a budget forum, you could help your manabase out by implementing a standard staple amid rotation, Sylvan Caryatid.
4x Drowned Catacomb
4x Island
6x Swamp
4x Watery Grave
Enchantment (6)
2x Liliana's Caress
4x Warped Devotion
2x Liliana of the Veil
Creature (4)
4x Delver of Secrets
Instant (14)
4x Boomerang
4x Cyclonic Rift
4x Remand
2x Surgical Extraction
4x Inquisition of Kozilek
4x Thoughtseize
Artifact (4)
2x Isochron Scepter
2x Sword of Feast and Famine