For a Legendary skin, you will need to spend 1,820 RP per skin, and for an Ultimate skin, you will need to spend 3,250 RP per skin. League of Legends offers players skins for their favorite champions with lower prices from The skins featured in the Night. Fruxo wrote: No the skins you reroll will not change anything. We start looking at options for the Victorious Skin in the Spring. Download the game, open mail and get all the rewards.
Once a player has obtained a Skin, the chance percentages reset.
Also, this reddit post and LoL Boards post tell that rerolling skin shards is random. With this in mind, we need to plan ahead for the Victorious skin, especially in comparison to a normal skin.