I Give Credit to myself. I was the first to put this up on youtube (if anyone else even has) You can check the date on youtube.
STEPS
1. Get to level 14 (any prestige)
2. Buy the Famas
3. Go down to where it shows Emblem and Clan tag as in video.
4. The lock picture is next to them showing that you cannot add those yet "wink wink"
5. Simply Hit A on both of them and the checkmark will show up still with the locks on it.
6. From here on out any gun you purchase you wont have to pay for Emblem and Clan tag on your gun.