Question about Steam Purchases. Please help !

Hello. You cannot trade it for 30 days, but you can gift it. ;P

By that, it means you can't send it via trade window (like for TF2 items, for example). You can, however, select the gift and send it to a recipient.

Gifting and trading are different. You can send the gift to a friend or a stranger via email right after you bought it. But lets say you buy the game because it's a really cheap price and you want to exchange that copy of the game for a different game. There would be the restriction, and you can even work around that by gifting it to your intended trade recipient.

You can add the winner and send directly through Steam or via email without adding. The email method doesn't always work as well because people don't check their email often.