I don't know. I tried to go to him once to get something to help her with the pain, but he wouldn't accept money. I honestly have no idea if it's just... a power game, or sadism, or some kind of checks and balances deal. I've heard that Regina has cast magic to help people that didn't come with a specific cost, but then Rumpelstiltskin... he offered a girl a chance to go to a ball and be able to escape a terrible life, but the cost was her firstborn child. He gave Snow a vial of potion to make her forget love and heartache, but she had to give him a hair. I don't know.