Does World of Warcraft Legions purchase include gametime and base game?

You will need to buy the base game first which automatically comes with 30 days of game time.

You actually have 3 options when you start playing WoW, but if you already have Legion it is recommended to get the base game right away as the expansion requires it. The base game then comes with 30 days of free game time. Having Legion when starting the WoW adventure has some serious benefits, such as not needing to level your first character through all previous expansions and of course access to the new class trial.

Free Starter:

• No costs
• Do whatever you want up to level 20
• You can NOT trade, join guilds or use the global chat (trade)
• You can NOT use races or classes restricted to expansions not included in the base game (right now: Legion -> Demon Hunter)
• You can NOT access content of expansions not included (Legion content starts with Level 98, so it's pretty hard anyway)

Base Game:

• Comes with 30 days of game time
• Requires paid subscription after the free time has expired
• You can do anything up to Level 100 (Warlords of Draenor)
• Includes all previous expansions
  • The Burning Crusade
  • Wrath of the Lich King
  • Cataclysm
  • Mists of Pandaria
  • Warlords of Draenor
• You can NOT use classes restricted to Legion (Demon Hunter)
• You can NOT access Legion content

Latest expansion (Legion):

• You can do anything up to Level 110
• Requires the base game and a paid subscription
• Includes a free character boost to Level 100, so you can start playing Legion right away
• Class trial! Try any class on Level 100 and decide later which one you want to play. You can as well apply your free boost on one of these. Very handy, if you don't know what class you want to play.