That depends entirely on your usage requirements. If you want to keep using your Koodo number while in the US, https://www.koodomobile.com/add-ons there are the US talk and text add-ons for 3, 10, 30 days. If you will have regular wi-fi access, it might be better to use a VoIP app instead. Or you could get a prepaid plan from MetroPCS or Cricket or use Roam Mobility instead. all are good options, depending on your needs.