How to make a simple GPS monitoring system "for family and friends"?

Question

satellite navigation

On sale, of course, I saw different options, but it's not that.
Typical options that I googled are either systems for a taxi or systems for monitoring a dog / child / personal car. Not that.

As I see it:
Approximately the same child monitoring system (a point on the map, nothing else is needed), only there are a lot of them (well, 10-15 points). Case - go for a ride with friends on quadrics, everyone has a tracker on their hand / in their pocket / in their backpack, anyone can look on their phone where the rest are now. Everything.

Free is nice, but not required. It is necessary that if there is a fee, then not "X money a year", but something like "paid X money, which is enough for a day, after a day it stopped working and don't worry until you need it again."

Answer 1

children's zhps watch for test subjects + application for the caretaker :)
if all adults with their smartphones, then any navigation application with a group location exchange.
osmand-telegram, osmodroid, for example.