I think it’s pretty important to point out that you don’t have to be familiar with Warhammer lore to enjoy the game. Group of adventurers pick up quests, kill bad things, and get new equipment is a pretty standard set up. If you do know your way around Warhammer you’ll find the fluff around the game even more enjoyable.
There is also a lot of additional content available for purchase. If you aren’t happy with your first four warriors you can pick up a high elf Archmage, human Brightmage, dwarf Trollslayer, high elf Shadow Warrior, ogre Irongut, human Warrior Priest, or a human Witch Hunter. The new character run 3 dollars each. There are two region packs that add new enemy types and open up new regions on the map. Each of these are 5 dollars and add skaven and savage orks to the game.
There are a series of Legendary Weapons. They each cost a dollar if you really want them. Finally there are Dungeon Packs. Each of these costs 3 dollars. One pack adds Necromancers and skeletons, the second adds vampires and zombies, and the third adds vampire themed tilesets into the dungeon. So you could easily drop more than 20 dollars on add-ons, but you don’t need to. The core game is a great turn-based dungeon crawler. I really recommended it to people before it was free, so if you haven’t downloaded it yet I highly recommend you do so.