ARAM Chance Scrolls

I think it would be cool to have the option to buy a scroll for a champ in ARAM which slightly increases the odds you may get that champ. Even like 5% to 10% chance and then if you have that scroll equipped and that champion gets selected, the scroll disappears and you would have to buy a new one. I understand this may defeat the purpose of random, but adding a slight chance percentage could make it even that much more fun!