What do you get when you mix Dungeon crawling with an Retail shop simulator? Quite a lot of fun, actually. Recettear's story is about a girl paying her family's debt back, and the only way for her to do this is to open a local adventurer item shop and sell goods. Half the fun is that the game switches back and forth between an action-oriented dungeon crawl to collect items and goodies, whiel the other half puts you in control of the retail portion of the game, haggling items to make the best profit you can.
Each week, You have to pay back a small portion of your debt or else you lose the game. This reminds me of the hated system of Pikmin and its' time limit, but that's really the only complaint I have about the game and it's definitely very doable once you get a feel for the game. There's a free trial on Steam so there's little reason not to give this game a shot. You can also download the demo from their official website.
Here's a quick video of some dungeon crawling.
Edit: If you play Vindictus, add me. West server, "FriedShrooms".