What is the average fee for a 401k plan?

Could you please provide an overview of the typical fee structure associated with a 401k plan? I'm curious to know what the average fee might be for managing such a retirement savings vehicle. Are there any standard rates or do fees vary significantly depending on factors such as the size of the account, the investment options offered, or the specific provider administering the plan? Understanding these costs is crucial for individuals seeking to maximize their retirement savings.