Well, there was Jarvan and Rumble at 4800. *shrug* Sona, Karma and Lux all at 3150.
I bought only Garen and Galio with RP, but I own every single champ with the exception of 8, not including Vayne; who I'll buy tonight. The eight champs I didn't buy because I don't like any of them. (I didn't have the IP to buy them on release, so I waited for Free Week, and tried them and made my decisions)
I consider myself a collector; I farm the ip to have 6300 for any champ on release day if I think they're interesting. Sometimes I decide later that it wasn't really worth it; I can only ever play one at a time, and some I've bought I never play. If you want runes, get runes first. Prioritize. There is such a thing as being an overly impulsive shopper.
Side Note: I own all those champs AND I have a 9set of nearly every useful rune. It's not impossible.