It costs me 300,000 to level up lol. There are some well worn farming spots later in the game. In the interest of saving you time, I'd advise you look up "Giant Lord farming" on YouTube, and not worry too much about grinding levels until you get there. At NG+8 (7?) I was getting almost 500,000 a kill. I've got a foolproof way to beat him now, it's just putting in time.