Yeah well it's a combiner Soul of Chogokin. Gunbuster is even more expensive at around 23,000 yen while Aquarion was 19,800 if memory serves correct. It is truly a line meant for the wealthy and the privileged. Lol. It is 100% worth the price for me though because the quality is unmatched.
I had the Military Version iirc and while yes, it was expensive, it was Really worth it. the die cast metal in it made it a sturdy figure and it was well built.
Pain in the butt to find though, I forget how much I later sold it for, but it was probably $300ish + Shipping. Try Yahoo!Japan.