My cat has scabs all over her neck and keeps scratching it. I have been avoiding taking her to the vet because I can't really afford to pay for a vet visit. She doesn't have them anywhere else on her body. If anyone knows what this can be please let me know.

It could be fleas.
When was the last time she was to the vet?

I have a cat who goes through a scratching phase every year and he's doing it right now. I'm sure in his case it's related to weather.

Regardless of what it's related to... I put a little Vitamin E from the gel caps on the scabby spots. It helps to sooth the scabby itch and also softens the scabs. And you can put hydrocortizone on it. My vet knows I use the Vitamin E and he's also the one who suggested the hydrocortitzone and said it was safe. It only takes a little dab on each spot. Although if it's a big problem, finding the source may be the only solution.

If it's fleas, you can get some Frontline. You shouldn't need to have a vet visit to get it, but you should get it from a vet and not order it online. It may be weather, like in the case of my cat. (Probably dry season. You can give salmon oil for that if you can get it down your cat. You can find this in some pet stores.) It also could be an allergy, either to fleas or food or something. If it's fleas you will eventually start seeing areas where you cat hangs out that contains little black speckled stuff, and you probably will start getting bit yourself, which will show up as just very small red circles.