I would like to add GPS to my rental. How do I do that? I am in Miami with the car already.

I think you must add it at counter. You can download waves app for free on your smart phone. Waves app have gps and will give you directions for free. No need to pay more money.

You have to add it while you're at the counter if you have a smartphone you already have navigation just use Google Maps or download Waze and connect your phone to the vehicles Bluetooth and it'll give you turn-by-turn right over the car speakers

Use the HERE app, free and it works great without a connection, just with your phone's GPS! GPS is too expensive with AVIS.

You can also go to bestbuy/target/Walmart and get a Garmin GPS with lifetime map updates for around 50-60$. Will be cheaper then to rent one.

Yes