Need to file state taxes for 2004 & 2005... resident of NJ but worked in NY. Which form (s) should I use to do my own filing and save some bucks?

Or if I want to save myself, pain & suffering, what's the average cost to use a tax professional? I'm single female, no kids.

For NY you file the NY form IT-203 (for non-residents). For NJ it's NJ-1040.

You will file NY tax return as nonresident. Then you will complete NJ tax return as resident. Then on NJ return, you will claim credit for taxes paid in NY by completing schedule A of NJ return.