You can ask for a raise, but there's no standard cost of living raise or other salary raise requirement, unless employees have a written employment contracts that say so, or a written employment policy that says so, or a labor union that collectively bargains for you.
If your employment is "at will," your employer can fire you, demote you, reduce your hours or salary or benefits, etc., all with no notice and for any reason or no reason, and you're free to quit with no notice for any reason.
Your employer can't illegally discriminate against you because of your race, sex, age, national origin, etc.,land they can't retaliate against you for exercising some lawful right like labor union organizing or "whistle blowing," and they have to adhere to their own policies, but beyond that, employees that are "at will" don't have the right to stay employed, let alone get raises.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.
Most employees are employed at will. Absent an agreement that says otherwise an employer does not have to give raises or even maintain the amount of remuneration it pays its employees. The employer is governed only by the forces of the market.