$14.95 will get you this:
It has a plug & play Grove connector, so you can easily add on GPS for a further $12.
If you can live without GPS, or can solder, then I also recommend LilyGo.
They have a slim wristband, like an activity tracker for about $20:
and a wristwatch with a larger screen for about $25:
All three of these are ESP32 based, so have ...