Renting champs in league?

I'm really down to try out a few new champs to increase my repertoire, but it's just too damn time consuming for me to save up 4.8 or 6.3k in IP for each new champ I wanna try, whom I may not even enjoy playing. Sure, there's a few champs that I can try for free each week, but out of the 100 or so champs, there are often quite a few that aren't selected; whom I'd also like trying.

I mean, I wouldn't mind dropping 500 IP to try out, say, before I have to commit with a massive 6.3k in IP (which, for me, equals like 2 or more weeks of gaming), so, why not set up some form of renting system in the League of Legends store? Costs could scale in contrast with the full-purchase cost of the champion so that you wouldn't be paying the same amount for a super cheap champ vs. a more expensive one, a feature which could be very helpful for newer/casual players in the league community ( ---> Me ).