Amazon offers Prime members the Monster High Freaky Fusion Neighthan Rot Doll for $10.99 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, it adds $6.25.) That's the lowest total price we could find by $4. It includes a hat accessory, doll stand, brush, and fusion diary.
Orders placed via 2-day shipping by December 22 will arrive in time for Christmas. (This option is free for Prime members, but an extra $11.73 for everyone else.)