Here are the current Renport prices linked below.
I have no idea how long you may want to converse with your family during your visit, but multiply your estimated calling time on ATT out per .50 a minute and see where you shake out. Maybe Renport makes sense, maybe it doesn't.
Signal/service has always been very good/consistent.
(FYI - click the mobile tab)
https://rancal.checkfront.com/reserve/