You know how in some games completing the tutorial gives you something. I was thinking you could get a free rune as an incentive for new players to try out the rune system. It doesnt have to be for doing the tutorial. It can also be for playing a certain number of games. Or reaching lvl 10 or something. Or maybe even for leaving newbie island. Just a simple rune (tier 1). Personally I dont see anyone buying Tier 1 or 2 runes. It seems like a waste of IP. Since reaching lvl 20 is fairly easy. Whereas completing a full rune page of Tier3 runes will cost you somewhere around 30k IP. Which is more or less the amount of IP you will have (without boosts) at lvl 25.
"Unique Seal of Apprenticeship"
Any of these would go well with it:
-Reduces time spent dead by 10%
-Reduces damage from creeps by 2
-Reduces damage from towers by 5
Of course this rune would have to disappear once you reach a certain level. Since the stats I suggested for it are somewhat overpowered for regular players.