The sale will last for a week (7 days) then a new sale will occur every Monday at 12pm PT. Note that if a particular Region is undergoing some technical issues or a Beta, the sale's duration will increase.
Riot Store | League of Legends Wiki | Fandom
leagueoflegends.fandom.com > wiki > Riot_Store
Legendary skins likely follow the same algorithm as the other cosmetics available within Your Shop, though specific information on how the skin is chosen has not been revealed. Due to a bug, Your Shop is temporarily disabled for all players, though i's expected to be up and running soon.
Riot provides insight into League's player-specific discounts in Your ...
dotesports.com > league-of-legends > news > riot-provides-insight-into-lea...
Overview. Your Shop Position A player receives six personalized offers of skin discounts, picked based on player match history over 6 months, prioritizing champions that have been played the most. The offering is determined in advance before the shop becomes available.
Your Shop | League of Legends Wiki | Fandom
leagueoflegends.fandom.com > wiki > Your_Shop
A category for these skins include one called legendary skins. These skins rework how the champion works, how their skill animation looks and their voice overs. But they cost 1820 riot points (which is really expensive). Every week, about 3 skins go on sale for 50% their normal price.
Do Legendary skins ever go on sale? - Arqade
gaming.stackexchange.com > questions > do-legendary-skins-ever-go-on-s...