The standard machines called Whimsical, Majestic and Gnarly are permanent, that is, they are always available. The gem cost of each machine depends on the rarity of the cards it contains. The rarity of each card will be represented by it's type: Common, Aqua, Gold or Black.
Each machine contains a different assortment of cards with different rarities, which you can discover by tapping the '?' button in the upper corner of the machine.
You will be able to see how many cards the machine has and its cost on the lower left corner of the machine.
The cards from these machines will allow you to complete the 'Standard' series.