Work back from the exchange day
Leave at least ten days for shopping and delivery. Close sign-ups a day or two before the draw.
Example: exchange Dec 23 → sign-ups close Dec 11 → draw Dec 12.
Pick a fixed budget
'Something reasonable' leads to awkward gaps. Set a clear cap; around ₩30,000 (about $20–25) is common for teams.
Share three rules up front
Stick to the budget, keep it secret until exchange day, and fill in your wishlist. Wishlists make shopping much easier.
For mixed teams, you can keep teammates from drawing each other.
On the day
Collect the gifts, then have each person guess their Santa before opening. Showing the reveal screen on a TV works well.