With 120+ Champions, 20 pages for Runes and Masteries are simply not enough

I like League of Legends most for its social aspect; I enjoy chatting with friends while playing a game or two. That means I like to try out champions from time to time even if I know nothing about them - I know my friends won't care, as we'll still have a blast regardless, even if we lose. However one of the things that holds me back from doing this more often is the limited amounts of Runes and Masteries pages there are. There are days where I'm like "okay, I'm going to try out five new champions today", but that means I would need to wipe clean five pages of Runes and Masteries, with is one quarter of the amount of space I have available, so most of the time, I don't even bother.

Please, Riot, at least let me BUY an upgrade. Or give me an option to store that kind of thing locally instead of online if you're concerned about Server space. I'd also like a quality of life change that warns me in case of exact duplicates in my Rune pages, I've had that issue once or twice.