Go to the department store in goldenrod city and play the lottery on tuesday
Where Can I Buy A Timer Ball In Pokemon Soul Silver?
You can also get them at the lottery on Saturday as well. It's on the sixth floor and is the #2 prize, so that means you'll probably end up getting lots of berries...
YOU can't GET A TIMER BALL
p.s you can trade one from d/p and platinum
p.s you can trade one from d/p and platinum
I don't think you can