Project Daily Grind (Mirror World LitRPG series Book #1) by Alexey Osadchuk

The ads enthused, "The virtual lands of Mirror World await you! Live out your most secret dreams in our world of Sword and Sorcery! Become a Great Wizard or a Famous Warrior! Build your own castle, tame a dragon, conquer a kingdom! All those desperate, lonely and insecure - Mirror World offers you a chance!"

But Oleg isn't meant to become a great wizard or a famous warrior. He'll never have a castle of his own. Neither will he ever tame a dragon. And he's definitely not the type to conquer a kingdom, however virtual it may be.

Oleg is doomed to toil away in the recesses of Mirror World's mines. His goal is to raise enough money for a heart transplant for his dying six-year-old daughter. The clock is ticking. Will he make it?