You purchase access to use /minions store in game. 

The in-game store allows you to purchase any/all of the following minions:

Miner (Mines the block in-front, upgraded miner smelts ore / can mine multiple blocks in front)
Slayer (Kills mobs within a pre-configured range)
Collector (Collects Items within a pre-configured range)
Feeder (Feeds minions with a pre-configured range)
Lumberjack (Chops wood & leaves within a pre-configured range)
Farmer (Farms farmland within a pre-configured range)
Fisher (Catches fish within water pools located in front of the minion)
Seller (Sells items found in its attached chest)

◘ Owner of the minions have to be online for minions to work, so make sure you purchase permissions on the right account!
◘ Read more about minions and minion upgrades here.

Block Spawner Minion

Minions (Place 5)

Minions (Place 25)

Minions (Place 50)

Upgrade (from 5-25)

Upgrade (from 25-50)