Sales/Pre-Season One

The list is ordered from the oldest to the most recent announcement made by the Riot Games Inc. 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

Period		Sales	Link
December 15 2009	December 15 2009	Freljord Ashe [S\|L] - 50% off	[1]
January 16 2010	January 16 2010	Rusty Blitzcrank [S\|L] - 25% off, removed from the store soon after.	[2]
January 18 2010	January 20 2010	Assassin Master Yi [S\|L] - 50% off	[3]
January 21 2010	January 21 2010	Sasquatch Nunu [S\|L] - 25% off	[4]
January 22 2010	January 24 2010	Kingpin Twitch [S\|L] - 50% off	[5]
January 29 2010	January 31 2010	Toxic Dr. Mundo [S\|L] - 50% off	[6]
February 6 2010	February 9 2010	Shadow Evelynn [S\|L] - 50% off Freljord Ashe [S\|L] - 50% off	[7]
February 23 2010	February 25 2010	Sasquatch Nunu [S\|L] - 50% off	[8]
February 26 2010	February 28 2010	Badger Teemo [S\|L] - 50% off	[9]
March 1 2010	March 3 2010	Nightmare Cho'Gath [S\|L] - 25% off	[10]
March 8 2010	March 10 2010	Pharaoh Amumu [S\|L] - 50% off	[11]
March 12 2010	March 14 2010	Assassin Master Yi [S\|L] - 25% off Emerald Taric [S\|L] - 50% off	[12]
March 19 2010	March 21 2010	Shamrock Malphite [S\|L] - 25% off	[13]
March 19 2010	March 21 2010	Golden Alistar [S\|L] - 50% off Noxus Poppy [S\|L] - 50% off Kingpin Twitch [S\|L] - 50% off	[14]
March 26 2010	March 30 2010	Mercenary Katarina [S\|L] - 50% off Freljord Ashe [S\|L] - 25% off	[15]
March 31 2010	April 2 2010	Toxic Dr. Mundo [S\|L] - 25% off Phantom Karthus [S\|L] - 25% off	[16]
April 1 2010	April 16 2010	Happy Urf Day Event Urf The Manatee Warwick [S\|L] - 99% off (first week) Urf The Manatee Warwick [S\|L] - 90% off (second week)	[17]
April 5 2010	April 6 2010	Nightmare Cho'Gath [S\|L] - 25% off Sasquatch Nunu [S\|L] - 25% off	[18]
April 9 2010	April 11 2010	Ruthless Pantheon [S\|L] - 40% off Armor of the Fifth Age Taric [S\|L] - 40% off	[19]
April 12 2010	April 16 2010	White Mage Veigar [S\|L] - 25% off Myrmidon Pantheon [S\|L] - 50% off Badger Teemo [S\|L] - 50% off	[20]
April 17 2010	April 20 2010	Dragon Knight Mordekaiser [S\|L] - 25% off Assassin Master Yi [S\|L] - 25% off	[21]
April 21 2010	April 23 2010	Recon Teemo [S\|L] - 50% off Emerald Taric [S\|L] - 50% off	[22]
April 24 2010	April 26 2010	Shadow Evelynn [S\|L] - 50% off	[23]
April 27 2010	April 30 2010	Red Baron Corki [S\|L] - 30% off	[24]
April 30 2010	May 2 2010	Big Bad Warwick [S\|L] - 30% off Red Riding Annie [S\|L] - 30% off	[25]
April 30 2010	May 3 2010	Infernal Mordekaiser [S\|L] - 50% off Vandal Jax [S\|L] - 50% off Mercenary Katarina [S\|L] - 50% off	[26]
May 4 2010	May 7 2010	Scuba Gragas [S\|L] - 30% off	[27]
May 14 2010	May 16 2010	Highland Tryndamere [S\|L] - 50% off Nottingham Ezreal [S\|L] - 50% off Phantom Karthus [S\|L] - 50% off	[28]
May 25 2010	May 28 2010	Sherwood Forest Ashe [S\|L] - 50% off Spooky Gangplank [S\|L] - 50% off Dragon Knight Mordekaiser [S\|L] - 50% off	[29]
May 28 2010	May 30 2010	Ruthless Pantheon [S\|L] - 65% off Freljord Ashe [S\|L] - 65% off Nightmare Cho'Gath [S\|L] - 65% off	[30]
June 1 2010	June 7 2010	Exiled Morgana [S\|L] - 30% off Hextech Sion [S\|L] - 30% off	[31]
June 4 2010	June 7 2010	Firefighter Tristana [S\|L] - 30% off Chosen Master Yi [S\|L] - 30% off Dryad Soraka [S\|L] - 30% off	[32]
June 9 2010	June 11 2010	Sasquatch Nunu [S\|L] - 70% off	[33]
June 11 2010	June 14 2010	Swamp Master Kennen [S\|L] - 50% off Toxic Dr. Mundo [S\|L] - 50% off Pharaoh Amumu [S\|L] - 50% off	[34]
June 15 2010	June 18 2010	Armor of the Fifth Age Taric [S\|L] - 50% off Badger Teemo [S\|L] - 50% off Shadow Evelynn [S\|L] - 50% off	[35]
June 18 2010	June 21 2010	White Mage Veigar [S\|L] - 50% off Myrmidon Pantheon [S\|L] - 50% off Desert Trooper Garen [S\|L] - 50% off	[36]
June 25 2010	June 28 2010	Spectral Fiddlesticks [S\|L] - 50% off Crimson Akali [S\|L] - 50% off Warrior Princess Sivir [S\|L] - 50% off	[37]
June 28 2010	July 2 2010	Red Card Katarina [S\|L] - 30% off All-Star Akali [S\|L] - 30% off	[38]
July 2 2010	July 5 2010	Matador Alistar [S\|L] - 50% off Bird of Prey Anivia [S\|L] - 50% off Emerald Taric [S\|L] - 50% off	[39]
July 6 2010	July 9 2010	Shamrock Malphite [S\|L] - 50% off Mercenary Katarina [S\|L] - 50% off Assassin Master Yi [S\|L] - 50% off	[40]
July 9 2010	July 12 2010	Chrome Rammus [S\|L] - 50% off Recon Teemo [S\|L] - 50% off Vandal Jax [S\|L] - 50% off	[41]

References

Skin Sales Super-Thread by Coreporeal