For many years I've rented Sat phones from the company at the link below. When you add up shipping, minutes, etc., they are always the cheapest that I've found. I've always been happy with their phones except last summer, the phone we got would receive text messages 3 or 4 days after the message was sent.
https://www.networkinv.com/services/satellite-rentals/ Also, there are message threads from last summer about renting sat phones with good information in them. Hopefully you can find them with the search feature.