Period: 9th of July to 1st of August, 2018
Skins: Riot Girl Tristana, Unchained Alistar and Dreadknight Garen
Only until the 1st of August you can get Riot Girl Tristana, Unchained Alistar and Dreadknight Garen for free. All you have to do is log into Riot’s Support Site and ‘Submit a Request’; option is in the top bar with the log in. Choose the request type ‘Free Limited Time Promotional Skins: Tristana/Alistar/Garen’ and check the boxes for the skins you want; there’s no problem if you request a skin you own so you can check all boxes. Check that the right region is selected, just in case. Click the ‘Submit’ button and the system will automatically grant you the skins. Remember to check that your account received the skins afterwards for peace of mind.
Take into account that both Riot Girl Tristana and Unchained Alistar are qualified as limited skins so their future is uncertain once the promotion ends. Dreadknight Garen will remain in the store for 975 RP. Given the ease with which the skins can be obtained consider yourself urged not to leave the giveaway for the last minute; servers may get chocked near the incoming deadline.
If you want more information about the skins you can check the reviews: Tristana, Alistar and Garen. Know that they may be old skins but they are nice and with only a simple request to get them there’s little reason not to get them. Hope you enjoy the skins.