Full Metal Jayce or Hecarim

This may be a very weird question, but should I get full metal jayce when he goes on sale, or when he goes on sale? Its been bugging me all day and I really want both. Which one should I buy? https://docs.google.com/spreadsheet/ccc?key=0Arh3w_1KfCECdEl3UUUyZ0pFSFBWcmpaTDVfa1lBUGc#gid=0