There's a formula that states just how much of omegas 3,6, and 9 are optimal, and if you wanted to be super-scientific, you could mix perfect ampunts of fish oil, flax, borage, evening primrose, etc. The main thing to shoot for is a good dose of these healthy oils, some fish and some flax daily does the trick really. Those are (relatively) cheap in bulk and in liquid form.
Also, if you cook with olive oil and eat nuts/peanut butter, etc, you're getting a lot of the omega 9 (I believe) whereas the others have mostly 3 and 6.
There are those expensive "perfect blend" oil caps available, but leave those on the shelf at GNC for the unsavvy retail kooks; they're waay too expensive! Get 1000 caps of fish oil from Matt (CNW) and a big bottle of flax for the fridge and you're loving your life....