Help. I can't take much more!

I have a female cat about 11-13 years old I can't really remember. In the past 5 months a drastic weight change has happened. She's become very skinny. Her eating habits have not changed other than she's literally like a dog when it comes to opening a bag of chips. She could be in the kitchen and within seconds she's busting through my door. It doesn't matter what I'm eating she's in my face or trying to take food out of my hand or off my plate. Just today she bit my lip trying to steal food. I have an almost 5 year old little boy and if she were to bite him trying to take food from him, I'd never forgive myself.

I just want options before I fork out money on a vet bill that leads to no answers.

extreme hunger and weight loss may be hyper thyroid. It shows up in the blood panel. The medication to control it is very affordable. 
 

What do you feed her and about how much?

I feed her just a regular dry cat food from tractor supply. And she has had access to food 24/7 since she was a kitten. I should be able to get her to the vet I'm about a week or so. If my mom will help me.

It could also be diabetes. Hunger and weight loss are common symptoms. The vet should do a senior blood work up. The specific test for diabetes is called the fructosamine.

See if there are any low cost vet clinics in your area. The cost is usually much more afforable than a regular vet office.

Like the others have already mentioned, a vet visit is definitely in order.  Any change in eating habits and certainly weight loss is cause for concern.  Your kitty needs a senior blood panel and to have her kidney function and thyroid checked and also checked for diabetes.  We're definitely not saying your kitty has any of these, but they need to be ruled out.  Also, as kitties age, their protein requirements go up.  You might want to supplement her dry food with a meat only canned food that's grain free.