That concept is flawed. You can get the VF-1S for dirt cheap when it becomes shelfwarmer, but the line will be dropped.
On the real side, I'm tired to see the Roy's and Hikaru's VF-1S keep popping up. Most people who collect these already have one at the minimum, so what they need are the 2-seater and other paint schemes. Yet if the heroic paint schemes won't sell, why even bother to bring out the less popular Valkyrie schemes?
With that in mind, I'd say that the line is way over its peak. The $250 price tag makes things even worse.
I remember paying $70~90 for a single Valkyrie and $130~$150 for the bundle with fast pack when the line was fresh.