Yes, having a money order would be a smart proactive thing to do. The prescription medication is another issue. You should bring it with you, the prescription too if you can arrange it. The US Marshal service will hold it in lieu of a new medical examination upon your Orientation & Admission period, and will most likely administer the dosage to you at the appropriate times of the day.
https://www.inmateaid.com/ask-the-inmate/should-i-bring-my-prescription-medicine-when-i-self-surrender#answer
Accepted Answer Date Created: February 18,2016