I've seen them being sold in past for 300m, 450m, and 500m. I would theoretically be aiming for the 500m range, since even though there's a new combo, a whole bunch are about to be released. It's negotiable, regardless.

I don't have that amount all in pure, so it'd have to be a mix of sP and CSC.

I also have a handful of CWs that I could trade:

[edit] Bought at 500m.