The Toy Cars Pack will feature nine rides (listed after the break, along with the Boost Specials), including an adorable miniature motorcycle. The Boost Specials DLC will pack two cars, featuring the previously unannounced Hawker Mech, which is allegedly customizable.
While the Burnout Store doesn't currently reveal pricing for these vehicles, an accidental release on Xbox Live Marketplace did (the content has since been removed). The Toy Car Pack was apparently offered this morning as a single download for 1,000 ($12.50). Each toy car was also available individually for 160 ($2), with the exception of the motorcycle, the Toy Nakamura Firehawk, offered for 240 ($3) -- the cars, minus the motorcycle, where also combined and offered in two separate packs for 480 ($6) each. The Boost Specials Pack was available as a single download for 400 ($5), or both cars could be purchased individually for 240 ($3). Obviously, the final pricing is subject to change.
Big Surf Island, a new island being added to the Burnout Paradise universe, is still without a date. Promising the "biggest jumps in Paradise City" the upcoming DLC will also include a new vehicle: the Dust Storm. Undoubtedly, additional details will be unveiled in the coming weeks.
Also released (and still available) on XBLM and PlayStation Store, is the new Time Savers Pack for 400 ($5), which grants purchasers "the keys" to the the standard retail edition's unlockable cars. Apparently, you can put a price on impatience.
Update: Criterion has confirmed these details through the in-game Burnout Store -- the original post has been altered to reflect the information found therein.