It was showing that the CW's were 300 csc right after the news post. But a few hours later I went back and it's all 500 csc again. Is this a glitch?

I haven't seen any at less than 500 CSC at all, and there are several in there I know have been there a long time.

Sandy Bob Cash Shop Credits 300

You may want to try clearing your cache (might take a couple times). I am seeing plenty of 300 CSC items.

Ok I just needed to clear my cache. It's working fine now c:

Thanks~

Welcome! Locking as resolved!