"Players will also be able to purchase digital sourcebooks, such as the Player's Handbook or Volo's Guide to Monsters, which will be available for $29.99. Adventure modules will run players $24.99. (Bradford notes that when D&D Beyond launches, the three core game books — the Player's Handbook, Dungeon Master's Guide, and Monster Manual — will be on sale for $19.99.)"
When this goes into full release, How will the payment method work. Is this like you purchase the PHB and you get access to the info in the PHB. What if you already own the 5e PHB will there be a way to get access at a discount or something?
It will be possible to purchase the PHB in digital format or you can do a subscription and share the PHB within a gaming group (Master Tier). About the discount nothing has been said, as far as I remember.
I'm loving the builder, though I was a little bummed to start building my current warlock character only to find out that The Great Old One patron isn't an option. Will this be added in later iterations?
For the beta test, only material from the SRD and Basic Rules is available. The other official material will be added at the final release. The price for that is still to be announced.