I'll assume you are aware that the price of a 2011 ProV1 is pretty much the price.  There are occasional deals like the recent (still current??) Loyalty Sale with buy 3 get 1 free.  Dicks/Golf Galaxy may still have some 2010 version stock left and was posted at under $40 a dozen.  Multiple dealers have X-outs for around 30, and there distributors of used/refurbished like Golf Balls Plus.  I've not had an issue personally, but there are some that have issues with quality.

Titleist is currently running their loyalty promotion.  Buy 3 doz. get one doz free  PLUS free personalization.  Great time to stock up with a great deal.  I don't think you are going to find better prices anywhere.  I bought mine through Carls Golfland.

In my 40 some odd years playing golf I have never found the top grade Titleist balls at a discounted price. They are the best and they have know problem selling at regular price. They are definitely worth the extra price.

Many pro shops, especially on public courses, sell slightly used balls that they have pulled from the ponds or woods. There are always Pro V1x balls in available there but you can't be sure how long they sat at the bottom of a pond or what condition they are in.

Rock bottom golf

Check ebay or get the ones marked "practice" they are just as good as the others and are tourney legal.