It wasn't well advertised (at all) but the freebie on October 30th was:
Cursed Mummy Wrappings
It wouldn't just appear in your inventory - you had to open the station cash shop window, and then buy it for 0 station cash. It's a clicky targetable mummy illusion that lasts 1 minute before extended buff duration code. After the 30th it continued to be available but for 400 SC.
One of the days around the 30th there was another less cool freebie:
Candy Dish
I think it was on sale for 0 SC on either the 28th or 29th. It looked like just one more random useless held item so 0 SC was still too high for me ;).
Double Station Cash One Day Only!
Double Your "Treats" on 10/29/11!
What better way to fill your Halloween goody bag than with DOUBLE STATION CASH®! Get Double Station Cash on Saturday October 29, 2011 starting at 12:01 AM PDT when you redeem any SOE Pre-Paid Game Card or buy Station Cash. Offer runs October 29, 2011, 12:01 AM PDT through 11:59 PM PDT; excludes purchase by mobile/SMS.
There are more tricks and treats in participating games throughout the SOE Trick-or-Treat Event! For more details visit www.soe.com/trickortreat.
Participating games include: EverQuest® EverQuest® II,;EverQuest® II Extended, DC Universe™ Online, Free Realms®, Star Wars®: Clone Wars Adventures™, PoxNora® and Magic : The Gathering – Tactics™