Robot Damashii [Side MS] Unicorn Gundam (Destroy Mode) is 3,675 Yen (inclusive of tax) while G.F.F.N. ReZEL is 6,300 Yen (inclusive of tax).
Images are from Tamashii Web Diary and Moeyo.
A review on G.F.F.N. ReZEL can be seen on Shinkimanga Blog.
Image is from Shinkimanga Blog.