When submitting Form I-765, Application for Employment Authorization to U.S. Citizenship and Immigration Services (USCIS), the agency will likely require you to pay a standard filing fee. This fee is nonrefundable. That means if your application for a work permit is denied, you do not get your money back. So, you'll want to make sure you meet the eligibility criteria for a work permit before applying! However, some people are either exempt from the fee or do not need to pay it because it's included within the fee for a larger application, as described below.
The I-765 filing fee required by USCIS in most cases is, as of 2022, $410. There's an added $85 fee for biometrics (fingerprinting) if you are either requesting Deferred Action for Childhood Arrivals (DACA), have an approved employment-based immigrant petition (or are the spouse or child of someone who does) but are facing compelling circumstances.
In addition, if you have an attorney help you with your application, the attorney will charge a fee for these services, as explained below.
In order to determine the filing fees, and whether one is exempt from them, an applicant must first determine their category of eligibility under the Instructions to Form I-765.
The following eligibility categories need not pay an I-765 filing fee for their first application (but we'll note below when they must pay a renewal fee for subsequent EADs):
For more, please see How to Apply for a U.S. Work Permit (EAD).
If you wish to have a lawyer help you prepare the Form I-765, the lawyer must charge for their services. For standard tasks such as these, most immigration attorneys charge a flat fee. That makes it easy to compare fees between attorneys. A typical fee for this particular service is from $250 to $500.
The lawyer might also separately bill you for expenses, such as the costs of photocopies and mailing documents to USCIS. You can ask the attorney to estimate these costs in advance.
And, you will have to have two color photos taken to send with the application, which will probably cost around $15.
For more on hiring an attorney, see these articles on Using an Immigration Lawyer.