A Note To All Players.
If you are attempting on filling up the remaining champions that you do not own, and do not have a preference for which one to buy first, you should buy 3 champion tokens. You pay 5100 IP in total and you are guaranteed one of the champions you do not have. Combine the shards you receive in the tool and you will receive a champion permanent. (ONLY DO THIS IF YOU DON'T CARE WHAT CHAMPION YOU WILL RECEIVE)
EDIT: Math.