PlayStation Plus required for multiplayer on PS4 games 

That is the only caveat we've heard so far. Stay tuned for full quote. Upon launch of the PS4, PS Plus members will get access to Drive Club, free. So while you will have to have a Plus membership for multiplayer - you will still be getting free games.

With a single PS Plus membership, users can continue to enjoy the benefits across PS4, PS3, and PS Vita systems.

The Instant Game Collection will extend to PS4 along with online gameplay.
In addition, one digital title will be rotated each month, including three of the new digital games introduced during the PlayStation E3 press conference: Don't Starve, Outlast, and Secret Ponchos.

These three titles will be available at no extra cost via the Instant Game Collection during the first year following the launch of the PS4 system.

PS Plus members will be able to use online multiplayer, broadcast and spectate games, cross-game voice chat, and the ability to "seamlessly join a friend's online game," all through Plus.

Users will still be able to play all single-player games as well as use all media services without subscribing to PS Plus.

PS Plus membership can be purchased through PlayStation Store and is available as a one-year membership for $49.99.

A three-month membership for $17.99, and a new a one-month membership option for $9.99.