If you are gambling in Act IV just for the $$$, choose the hermit in the fields. I also find that choosing a gambler right next to a fire or offering free lodgings is quicker than "reloading" the scene via a location change. With the hermit, gamble all he's got, then use the fire to meditate for 1 hour. Rinse and repeat. As long as you use Igni to light the fire, you aren't spending anything on the meditation.