My cats love that stuff.

You might also try pure aloe vera gel (it's clear) on her itchy patch;
if you have the plant, you can break off a leaf & squeeze the gooey liquid out of it & put it on her bad spot.

When I adopted my cat she had pretty dry fur and the vet said a small ammount of fish oil was fine - but just a few drops a day. If you feed good canned food it probably already has some kind of oil in it - may be fish, salmon, flax or avocado, depending on the brand. You don't want to overfeed the the fish oil, so check your food to be sure it is not already in there.

After two years of top-quality canned food my cat now has a sleek, shiny, soft coat. Big improvement.

I saw this recommended on an online vet site; they were selling a small bottle of oil for about $20 counting shipping. But I figured I could use my own fish oil, which drop for drop would be much less expensive. But I wasn't sure from that site whether I should be feeding it to her, or rubbing it into the dandruff spot!

Using your own fish oil should be fine - I used to puncture the capsule, give the cat 2-3 drops then swallow the capsule myself. I don't think it would hurt to put a little oil on the outside of the cat but she might start attracting other cats (or fishermen) if she starts smelling like fish!