I'm really getting into the demo now, can't wait to get the full game.
The haggling is ok once you find the sweet spot; I usually go around 125% as you still end up with a profit and you can also get exp combos for multiple sales in a row where the customer accepts your first asking price. I've also found that this is quite a good point for the nearest the pin exp bonus' but I've only got a few of those.
Also, hated my first dungeon crawl, now I'm addicted; did the same one 3 times and smashed the shit out of my first repayment

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Would definatly recommend after giving the demo a bash as its such a cool concept! Only anoying thing is the overly cutesy graphics, but after an hour or so it starts to become charming and really fits the overall feel of the game. And the humor, OMG, this game trolls the shit out of traditional JRPGs, its awesome!