Why do you guys want GPS or a map on SXM? If you drive one way and it's not there, go the other way.
Also use your regular phone on wifi. No drama. If you have WhatsApp you can hook up to wifi as well and make calls.
No charge. Really. Not a big deal. Don't overthink it. You will be fine. And chippie is cheap but you won't get messages like you would on wifi.