Their posts says:
Don’t miss the SOE Weekend Blitz half price sale!
Get half price on every station cash item in-game!
Hurry because this is a limited time event! It ends on Monday June 18, 2012*
*Offer valid from 12:01AM PDT 6/16/2012 to 11:59PM PDT 6/18/2012; PC only.
(Note that time is USA based time)
Participating in-game marketplaces are:
- Free realms
- DC Universe Online
- Star Wrs Clone Wars Adventures
- Magic the gathering Tactics
It's basically a 50% off, if you bought your station cash at normal price.
For me it's an even better bargain, since I bought Station Cash at a x2 sale, and buying half price items is like 75% off!