Question about the snowdown shop

My friend had a lot of champs he doesn't own selected for his snowdown shop (he played them during free week, he's level 23).

He has Arcade Hecarim off for 70% but he doesn't own him, so with hecarim included it's worth 669 RP. He doesn't want to spend any money so I came here to ask for him: If he unlocked Hecarim with IP would it lower the price? Would it go down to 405 RP? Can he get rito to gibe him 5 rp if he does something?