Everything is free.
As a dwarven miner just starting out in the mining business you dig for a variety of ores, gems, precious metals. You level up in your mining skills, digging for more valuable things with time, earning more money. With the money earned you will be able to make your mine your home and buy fancy decoration, furniture, gadgets, etc…
Use the cursor keys to dig your own mine. Be sure to always have enough wood when digging or your mine will collapse and trap you. At the shop you can sell your ores and gems, buy wood and better pick-axes. At first you can only dig one type of soil but with better pickaxes and higher experience you can dig harder rock and find more expensive ores and gems.