The list is ordered from the oldest to the most recent announcement made by the Riot staff regarding skin sales.

Pre-Seasons Seasons
Pre-Season One Season One
Pre-Season Two Season Two
Pre-Season Three Season Three
Pre-Season Four Season Four
Pre-Season Five Season Five
Pre-Season Six Season Six
Pre-Season Seven Season Seven
Early Sales


Period Sales Link
September 13
2011
September 16
2011
PantheonSquare Ruthless Pantheon [S|L] - 50% off
KayleSquare Viridian Kayle [S|L] - 50% off
GragasSquare Gragas, Esq. [S|L] - 50% off
[1]
September 16
2011
September 19
2011
KarthusSquare Phantom Karthus [S|L] - 50% off
MalzaharSquare Vizier Malzahar [S|L] - 50% off
BrandSquare Apocalyptic Brand [S|L] - 50% off
[2]
September 20
2011
September 23
2011
UdyrSquare Black Belt Udyr [S|L] - 50% off
KatarinaSquare Bilgewater Katarina [S|L] - 50% off
NasusSquare Dreadknight Nasus [S|L] - 50% off
[3]
September 23
2011
September 26
2011
VayneSquare Vindicator Vayne [S|L] - 50% off
KassadinSquare Pre-Void Kassadin [S|L] - 50% off
LuxSquare Sorceress Lux [S|L] - 50% off
[4]
September 27
2011
September 30
2011
ShenSquare Blood Moon Shen [S|L] - 50% off
GangplankSquare Spooky Gangplank [S|L] - 50% off
RammusSquare Molten Rammus [S|L] - 50% off
[5]
September 30
2011
October 3
2011
SorakaSquare Dryad Soraka [S|L] - 50% off
VladimirSquare Count Vladimir [S|L] - 50% off
CaitlynSquare Safari Caitlyn [S|L] - 50% off
LeBlancSquare Prestigious LeBlanc [S|L] - 50% off
[6]
October 4
2011
October 7
2011
MalphiteSquare Shamrock Malphite [S|L] - 50% off
Twisted FateSquare Tango Twisted Fate [S|L] - 50% off
WarwickSquare Big Bad Warwick [S|L] - 50% off
[7]
October 7
2011
October 10
2011
Lee SinSquare Acolyte Lee Sin [S|L] - 50% off
IreliaSquare Nightblade Irelia [S|L] - 50% off
VeigarSquare White Mage Veigar [S|L] - 50% off
OlafSquare Glacial Olaf [S|L] - 50% off
TeemoSquare Recon Teemo [S|L] - 50% off
[8]
October 11
2011
October 14
2011
RumbleSquare Rumble in the Jungle [S|L] - 50% off
BlitzcrankSquare Boom Boom Blitzcrank [S|L] - 50% off
CorkiSquare Hot Rod Corki [S|L] - 50% off
[9]
October 14
2011
October 17
2011
AkaliSquare Blood Moon Akali [S|L] - 50% off
UrgotSquare Butcher Urgot [S|L] - 50% off
Miss FortuneSquare Waterloo Miss Fortune [S|L] - 50% off
WarwickSquare Tundra Hunter Warwick [S|L] - 50% off
Xin ZhaoSquare Viscero Xin Zhao [S|L] - 50% off
SingedSquare Surfer Singed [S|L] - 50% off
[10]
October 18
2011
October 21
2011
JaxSquare Jaximus [S|L] - 50% off
SingedSquare Hextech Singed [S|L] - 50% off
GarenSquare Desert Trooper Garen [S|L] - 50% off
[11]
October 21
2011
October 24
2011
SwainSquare Northern Front Swain [S|L] - 50% off
MorganaSquare Sinful Succulence Morgana [S|L] - 50% off
ShenSquare Frozen Shen [S|L] - 50% off
[12]
October 25
2011
October 31
2011
Cho'GathSquare Nightmare Cho'Gath [S|L] - 50% off
KarthusSquare Grim Reaper Karthus [S|L] - 50% off
YorickSquare Undertaker Yorick [S|L] - 50% off
[13]
October 28
2011
October 31
2011
OriannaSquare Sewn Chaos Orianna [S|L] - 50% off
WarwickSquare Feral Warwick [S|L] - 50% off
FiddlesticksSquare Spectral Fiddlesticks [S|L] - 50% off
[14]
November 1
2011
November 4
2011
LuxSquare Commando Lux [S|L] - 50% off
AniviaSquare Noxus Hunter Anivia [S|L] - 50% off
SorakaSquare Divine Soraka [S|L] - 50% off
[15]
November 4
2011
November 7
2011
Miss FortuneSquare Road Warrior Miss Fortune [S|L] - 50% off
AniviaSquare Hextech Anivia [S|L] - 50% off
NasusSquare Galactic Nasus [S|L] - 50% off
[16]
November 8
2011
November 11
2011
SkarnerSquare Earthrune Skarner [S|L] - 50% off
NidaleeSquare Pharaoh Nidalee [S|L] - 50% off
UdyrSquare Primal Udyr [S|L] - 50% off
[17]
November 11
2011
November 7
2011
Twisted FateSquare High Noon Twisted Fate [S|L] - 50% off
CassiopeiaSquare Siren Cassiopeia [S|L] - 50% off
NasusSquare Pharaoh Nasus [S|L] - 50% off
[18]
November 15
2011
November 18
2011
VeigarSquare Baron Von Veigar [S|L] - 50% off
LeBlancSquare Wicked LeBlanc [S|L] - 50% off
OlafSquare Forsaken Olaf [S|L] - 50% off
[19]
November 18
2011
November 21
2011
LeonaSquare Valkyrie Leona [S|L] - 50% off
SionSquare Warmonger Sion [S|L] - 50% off
KayleSquare Unmasked Kayle [S|L] - 50% off
[20]
November 22
2011
November 25
2011
NocturneSquare Ravager Nocturne [S|L] - 50% off
Kog'MawSquare Caterpillar Kog'Maw [S|L] - 50% off
ZileanSquare Groovy Zilean [S|L] - 50% off
[21]
November 25
2011
November 28
2011
The Legacy Skin Project:
NunuSquare Sasquatch Nunu [S|L] - 75% off
EzrealSquare Nottingham Ezreal [S|L] - 75% off
PoppySquare Blacksmith Poppy [S|L] - 75% off
EvelynnSquare Masquerade Evelynn [S|L] - 75% off
GragasSquare Scuba Gragas [S|L] - 75% off
SivirSquare Spectacular Sivir [S|L] - 75% off
Dr. MundoSquare Mr. Mundoverse [S|L] - 75% off
Dr. MundoSquare Toxic Dr. Mundo [S|L] - 75% off
KennenSquare Swamp Master Kennen [S|L] - 75% off
SionSquare Hextech Sion [S|L] - 75% off
ShenSquare Yellow Jacket Shen [S|L] - 75% off
AnnieSquare Red Riding Annie [S|L] - 75% off
NidaleeSquare Leopard Nidalee [S|L] - 75% off
MordekaiserSquare Dragon Knight Mordekaiser [S|L] - 75% off
Kog'MawSquare Sonoran Kog'Maw [S|L] - 75% off
TwitchSquare Kingpin Twitch [S|L] - 75% off
RyzeSquare Professor Ryze [S|L] - 75% off
MalphiteSquare Shamrock Malphite [S|L] - 75% off
TryndamereSquare Highland Tryndamere [S|L] - 75% of
AmumuSquare Pharaoh Amumu [S|L] - 75% off
TeemoSquare Badger Teemo [S|L] - 75% off
[22]

References

Skin Sales Super-Thread by Coreporeal