1. Go to an Apple store or any store such as BestBuy or Rogers.
2. Make sure that the store you go to has a phone with AT&T, Fido, or any mobile networks on it.
3. Text your friend so you can find out the number of the phone.
4. Tell your friend to login to the League of Legends account and click "Mobile Payment" and purchase the RP with the number on the store phone.
5. When the text comes reply with "YES"
6. BAAM, you just got yourself free rp.
[I know this method takes a while.... but still it's free RP]