My understanding of the ADA Title III Requirement is the Hotel is only required to make available to you the same service as it provides to all it's other guest without additional charge. Since the Hotel is charging able-bodied persons to pay the $10, they can charge the disabled person $10. Much the same as your room. Everyone pays for their room, and they cannot charge extra to a person with disabilities. Having said this, I've gotten Hilton Hotels to waive the Refrigerator fee before.

ADA Title III Technical Assistance Manual. Section III-3.0000 General Requirements