Boost is a utility in the game Temple Run. There are two types of Boosts: Boost and Mega Boost. Boost boosts you ahead 1,000m for 2,500 coins, and Mega Boost boosts you ahead 2,500m for 10,000 coins. You can upgrade the "Head Start" ability so the boosts will cost less money. It is advisable to buy a Mega Boost if you are trying to achieve a high score or if you want to get the objectives Novice Runner, Sprinter, Athlete and Steady Feet. You will need to purchase them from the shop first, then use when starting a new game.
In Temple Run 2, this utility is known as Head Start and Mega Head Start. But the cool thing about the head starts in Temple Run 2 is that you can upgrade them to cost less coins. It's advisable for you to upgrade the Mega Boost because initially, it costs 10,000 coins. So if you want to not waste that much of your precious coins on them, just buy the upgrade. Unlike the first game, it is not stackable. At the start of each game, the button appears if you have enough coin, and tapping the button activates the corresponding power and takes your coins at the same time.