To get a Tinder boost, you just have to tap on that little purple lightning sign. You can then buy some if you need!
As usual with Tinder, pricing depends on your age, gender and location. At the moment, it is roughly 8 USD per boost, with decreasing prices if you buy bundles!
Hold on before you rush there. You also get a monthly free boost with all subscriptions: Tinder Plus, Tinder Gold and Tinder Platinum.
Sounds good, but I can't help shedding a tear thinking of the early days with the free weekly boost! Good times!
Then you are free to use them when you want clicking that purple button: Make it them likes rain!
Warning! Tinder can be sneaky. Can't count the number of times I clicked that button by mistake, or ended up clicking boost again button after a boost. You have been warned!