Can you get maser balls in diamond and pearl without using cheats or the lottery

Master BallThe Master Ball can be gotten, like you said, with Action Replay or lottery, but you can also get it by transferring over Pokemon that naturally have it (like Mew, I believe) when you encounter it in the wild. Most people get their Master ball from Cyrus after you beat him in Veilstone City. He just gives it to you. You can also clone an item like a Master Ball using a trick that involves Double Battles.