I am looking for a gps/navigation system for around $500. I am not sure what exactly I need so I will tell you the use and you can tell me what I need.
I will be using in on a basstender 11.3. I am going to mark flats in the river at low tide that may hold stripers at high tide. I also may need help finding my way back to the boat ramp.lol

I am not sure how they work. Do I need to buy a card with the information on the geograhic area that I am in or can I just buy it and trun it on?