I've looked into getting a modern bike computer but they all seem like a *lot* of money for what they do. So I just use an old smartphone (Samsung Galaxy S5) that has no service, and run OsmAnd on that. That gets me mapping, and those other statistics (speed, elevation, etc., over the course of the ride, plus a saved GPS track of where I went). I have a metal bracket from AliExpress on the handlebars for it. Basically, this was free since the phone was old and I don't use it as a phone any more. The bracket was $13 on AliExpress.