BR><BR>Would it be appropriate to mention in my cover letter that I am willing to pay ... BR>I understand the cost of relocation may be an issue for some companies when deciding who to hire ...

This line shows your reader you fully read the job description, and that location (or relocation) won’t be an issue. Related: 3 Cover Letter Closing Lines That Make Hiring Managers Grimace ...

"One of the best cover letters I ever saw was written by a gentleman ... and your availability for relocation or travel. Related: To apply for jobs that match your skills, visit the Military ...