Talk:Nasus/SkinsTrivia/@comment-124.6.181.167-20110811010051

"Summoners who arrive in costume will receive a code redeemable for the now limited edition Riot Squad Singed skin, which is being retired to make room for a brand new face on the Riot squad. This will be your last chance to add Riot Squad Singed to your collection."

Taken from http://na.leagueoflegends.com/board/showthread.php?t=1082137

This clearly shows that Riot Singed will no longer be sold and that Riot K-9 Nasus will take its place as the code giveaways to Pax attenders. Meaning he won't be sold like a regular skin