"As of 24th of November, 2014 all new games purchased in Steam as a gift and placed in the purchaser's inventory will be untradable for 30 days. The gift may still be gifted at any time. The only change is to trading."
I will not go first, after your half of the trade has been made you will be gifted Garry's Mod by myself. I will also +rep your profile. If you feel I cannot be trusted I will make a statement saying that I will gift you Garry's Mod after your half of the trade, which you can happily screenshot along with my profile to report on steamrep.com. If you do not agree with this, please leave as this will not be the trade for you. Thank you for understanding.
Garry's Mod - 3 keys
Garry's Mod
3 Keys