Save the RP till level 20, get your tier 3 runes.. after that you can buy all the champs you want. (save some RP till level 30 for the other runes)
If you didn't spend much at the beginning of the game you will have around the 20k IP, that's enough to get a full rune page
o and my main champs are:
Jungle - Lee Sin, Jarvan IV, Fizz, Hecarim, Fiddlesticks.
Top - Lee Sin, Jarvan IV, Fizz, Wu Kong, Zed, Akali.
Mid - Lee Sin, Fizz, Zed, Veigar, Akali, Lux, Akali.
ADC - Ezreal, Draven.
I totally can not support at all.. if I had to, I would choose the support I like to play with..
Support - Blitzcrank, Taric, Sona.
as you see the most lanes I play are top and jungle.. I hardly go anywhere unless if they are taken already :|.
I can jungle almost with all the champs and it turn out great if I am with my premade group
.
I'm playing on EUW - Sky High Fly.