https://www.dndbeyond.com/marketplace/source/2

So please answer me, because this is really not clear, and the way they word it is vague.

IF i buy the Player's Handbook at $29.99

Do i still need to buy the Additional Purchase Options of
Subclasses. Backgrounds. Feats. Subraces. Spells.

because as i have it. you buy the book for the "words" but cannot use it on your D&D character builder.
and still need to buy all the Aditional content even after you have the book. to use it with D&D beyond character builder.

That is correct, if you purchase the Compendium version of the book, it's just like buying the book, except in a digital format. You don't get access to any of the digital tools DDB offers.

The Compendium Content bundle does not grant access to all the content’s options in the rest of the toolset, such as the searchable listings, character builder, or digital sheet.

/e Oh shoot, I for some reason thought the PHB was $39.99. Purchasing it for $29.99 does give you everything, like the below have mentioned.

Keep in mind that Jusblazm is talking about purchasing of compendium content only.  If you buy the full version of the book then the book and its contents are available in the builder.  You just need to carefully read the description of what you are purchasing, to make sure it is what you are looking for, based on the price you gave I'm pretty sure that is for the version that is both builder and compendium.

Josef is right; $29.99 gets you both the compendium and the content (races, subclasses, feats, spells, etc.) in the character builder and the listings. The individual prices are for those who don't want to buy the entire "book."  Compendium only for the PHB is about $19.99 and doesn't include the content in the character builder and the listings.  That's what Jusblazm was referring to, but the price point you listed is the whole kit and kaboodle (for the PHB content).

I'm still trying to figure out what I purchased for $29.99.  After I got done with the transaction, I received no email receipt or book.  I figured I was getting the digital version, but what digital version did I purchase?  I can't seem to find it.  (If it's not obvious, I'm new to D&D)

extending onto this question.

you have the full package at $29.99

just the book with out the character builder features is $19.99

additional options

sub classes $9.99

backgrounds $3.99

Feats $3.99

subraces $2.99

Spells $4.99

total:$25.95

if you have a physical copy of the PHB could you just buy each of the additional options for a total of $26 to unlock them in the character builder?

Yes: you wouldn’t have access to the compendium (the full text of the book) but it would give you access to all those bundles in the character builder.  The one thing I’m not sure about is whether or not you’d get all the equipment, IF there are equipment items that are in the PHB but not the Basic Rules and SRD.   If you decided later you wanted the compendium,  you could pick it up for just $4.04.

Quote from Stormknight >>

All equipment is available to all users (it's not tied to specific sourcebooks).

 Thanks for clarifying that, Stormknight!  I didn’t have a way to check easily.

I've been trying to write my own character builder for about a year and stumbled onto DDB.  AMAZING!  My question is, should I buy the PHB, will my players be able to build their characters with the extra content, or I'm the only one that can do it?  As our DM, I don't really need the PHB, I want it more for my players, but don't want all of them to have to buy the same things, and don't want anyone sharing account information.

Thanks.

Quote from Nolabotomy >>

I've been trying to write my own character builder for about a year and stumbled onto DDB.  AMAZING!  My question is, should I buy the PHB, will my players be able to build their characters with the extra content, or I'm the only one that can do it?  As our DM, I don't really need the PHB, I want it more for my players, but don't want all of them to have to buy the same things, and don't want anyone sharing account information.

Thanks.

 If anyone in the campaign (DM or otherwise) has a master tier subscription to DDB, then they can enable something called “content sharing” and then every character in that campaign can use any book purchased by any player (including the DM) as long as those characters are in that specific campaign when they do it.

Quote from Nolabotomy >>

I've been trying to write my own character builder for about a year and stumbled onto DDB.  AMAZING!  My question is, should I buy the PHB, will my players be able to build their characters with the extra content, or I'm the only one that can do it?  As our DM, I don't really need the PHB, I want it more for my players, but don't want all of them to have to buy the same things, and don't want anyone sharing account information.

Thanks.

 
Only you.

However, you could create homebrew copies of the character options (Race, feats, etc).

Or you can get a Master tier subscription. With this if you are in a campaign on D&D Beyond you can enable Content Sharing. When a campaign has had Content Sharing enabled by somebody with a Master Tier subscription then any purchased content from any player will be shared with everyone else in that campaign.

For example: let's say a group has Adam, Brenda, Christie and Dave the DM. Dave creates a campaign on D&D Beyond and invites the others.

Adam purchased The Player's Handbook (PHB)
Brenda purchased Xanathar's Guide to Everything (XGTE)
Dave purchased the Dungeon Master's Guide (DMG)
and Christie got a Master Tier's subscription.

Christie enabled Content Sharing.

Now Adam, Brenda, Christie and Dave ALL get to access PHB, XGTE and the DMG.

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EDIT: Ninja'd by Sposta! >.<