Is there a fee for submitting prior art citations or written statements to the USPTO?

No, there is no fee required for submitting prior art citations or written statements to the USPTO for placement in patent files. As stated in MPEP 2202:

Submission may be made without payment of a fee.

This applies to both prior art citations and written statements concerning claim scope. These submissions can be made independently of any reexamination request.

To learn more:

Topics: MPEP 2200 - Citation Of Prior Art And Ex Parte Reexamination Of Patents, MPEP 2202 - Citation Of Prior Art And Written Statements, Patent Law, Patent Procedure
Tags: Citation Submission, USPTO fees, Written Statements