I paid cash. Hmmm I didn't have a checklist and I don't remember taking anything interesting with me(did all the tests and psych assesments there with their help). but my mother was with me and she would help if I needed anything. I think there is a thread about what to take with you for SRS though, just not a PAI patient. (try googling what to pack for SRS)
If I had more time before surgery I would probably get electrolysis for the skin that would go inside. There is a chance they might not be able to remove all the hair roots during surgery. It is harder to remove them post-op.