From PLL XXXVI, available at https://www.twitch.tv/videos/146267937
Discussion of boost items begins about 03h47m in.

Available 16 June

($18) Tales of Adventure: A Realm Reborn - Clears up through 2.55 "Before the Dawn".
($25) Tales of Adventure: Heavensward - Clears up through 3.56 "The Far Edge of Fate".
-- Grants you a chocobo with a random name.
-- Sets your GC to the one affiliated with your starting city.
-- Flags MSQ dungeons complete
-- Flags side dungeon quests complete, but dungeons themselves not complete

($25) Tales of Adventure: JOB - Sets any one job other than RDM/SAM at Lv60
-- Lv30-Lv60 quests complete and actions learned.
-- Includes complete set of Lv60 gear for that job.
-- Limit one job boost per account for now



If you buy just the MSQ skipper, you will have to grind out 50-60 levels on your own in order to access the next part of the story.

If you buy just the job boost, you will still have to go through the MSQ yourself, but you'll be able to binge quest without running into level locks.