DoctorDelt

Lyev Skyknight might be nice.

Don't forget cloudshift!

Since you're going casual, what about copy enchantment? You could use it alongside any of your other enchantments but it would be particularly vicious when used on Curse of Bloodletting or Thirst. Even with Misfortune you have the ability to then put curses on faster.

let the insurance fruad begin...

I don't like this deck at all. If I were you I would just give all those cards to someone in your play group...

Keep the bat, you need flying chumps... the guards are nice as well but the tithe drinker might be more useful given the cost & early lifelink potential.

I've been running Rhox faithmender in my extort deck to great effect - I recommend him for any lifegain deck. If you want to be a prick, you can also run Felidar Sovereign though don't count on playing this deck often after winning that way, unless you can take the aggro it'll bring.
don't forget removal in multiplayer - I'd add a few o rings when playing against more than one opponent. A mutilate or two is always useful as well, especially if you have blind obedience out because you can still extort.

Happy to help! My first serious deck was based around this mechanic, so I love to give my 2-cents on the good 'ole Guttersnipe!

Here's one that's similar to what I run now:

http://www.mtgvault.com/doctordelt/decks/goblins-drakes-snipes/

One last bit (up to you): I use cackling counterpart pretty religiously in my guttersnipe deck. It's extremely useful, especially when combined with stuff like Dual Casting or Increasing Vengeance. Say you have one Guttersnipe on the battlefield; he's already annoying to your friends and will likely be the victim of removal inside of a few turns. If he lives through one turn, though, and you can Counterpart him twice using Dual Casting or Increasing Vengeance, you've just done a total of 6 damage directly to all opponents. Next turn you'll do 6 damage for each spell you cast (& if you flashback the counterpart you'll do even more next turn.... it's a vicious cycle).

Another thing I've been doing lately is Massive Raid + Dual Casting / Increasing Vengeance. Depending on the tokens you have control of, this can kill an opponent inside of a turn... sometimes two at once since I run Krenko Mob Boss and other Goblin token stuff.

I like it! Lots of control!

Maybe consider putting more cards with flashback in. Increasing Vengeance would be the biggest one I would recommend for this deck, or Think Twice. Also, why no love for the Goblin Electromancer? Flux Charger & Temporal Mastery would also work quite well here.

You need to put Vizkopa Guild Mage in this deck, the combo with Exquisite Blood is just too good to let go. I'm also fond of High Priests of Penance to dissuade attackers and do some removal. I'd replace the Executioner Swings with Smites, they cost less and guarantee a kill while keeping your creature. Maybe cut the Debt to the Deathless down and add a finisher or two: Griselbrand and Blood Baron of Vizkopa are my two personal favorites. Check out this deck for some inspiration... this is the most effective extort deck I've seen:

http://www.mtgvault.com/darkmerc/decks/infinite-extort/

I've got one up as well that I like, but I've changed some things around.

Sands of Delirium also ;)

I had an idea for a deck that used this same mechanic. Cool idea!

Clever idea, this is the first Merfolk deck I've seen that I could see myself playing!

blind obedience is always helpful!

I agree about Hidden Strings. The best value it gives is the ability to untap mana or creatures with abilities.

Pure white lifegain?

Rhox Faithmender !!!
Angelic Skirmisher !!!
Elgaud Inquisitor
Ajani's Sunstriker

Riot Control

*Nod* My friends' Spirit/Tap Deck uses Sleep and it has won him the game a few times. The new Hidden Strings might be a good addition also; especially if you had it on a stalker with Niblis of the Breath on the field. 3 Taps every turn for 2 mana!

at $150, I wouldn't exactly call this budget, which is usually reserved for >= $20.00

Cool deck tho.

Stuffy Doll?

You're already splashing Golgari.... Corpsejack Menace? Maybe Jared Golgari Lich Lord instead? His 3 cost added to your crazy counters would make quick work of some oponnents.

Mutilate or Killing Wave are good board clear - this is necessary for your deck. I've changed the course of several games with a well placed board clear.

Pontiff is useless in a deck that is mostly extort, anyway. You'll never have the mana.

I also recommend adding the High Priest of Penance to scare your buddies away from attacking you.

Extort decks can be very low power & they piss your friends off, you want them to think twice before attacking.

Smite is great for an extort deck - low cost, so you can really make 'em pay

Exquisite Blood is a must!!! Especially in multiplayer.

Blind Obedience is annoying, low cost, & can carry extort even if your board is wiped.

Only keep one end-game card like Teysa in your deck... two at the most.

I recommend (& often use):

Griselbrand
Obzedat, Ghost Council (AWESOME w/ Exquisite Blood)
Blood Baron of Vizkopa

I'm sure you'll see the trend. just remember that MOST of your cards should be 2-3 cost.

Lithion is 100% right: You want to be able to play fast - you shouldn't be casting spells often if you can't also extort. Bump in the Night is good for this.

Also: Havoc Festival @ .31/card these are cheap