Used & Refurbished Garmin Forerunner 235
Since this cheap Garmin watch is already a few years old (it was released in 2016), you can get one for about $100, which is a small price to pay for a watch with built-in GPS, a heart-rate monitor, and sleep tracking. Did I just say sleep tracking? Yes, sleep tracking. That’s a feature that Apple Watches just recieved in 2020 with Apple's newest Watch OS7 update. And since this watch is waterproof, you can also wear it in the shower or use it to track your swims.
And if one GPS antenna wasn’t enough, this watch also includes GLONASS support, which gives it the ability to check Russian location satellites to get an even more accurate reading on your positioning.
This watch can even estimate your VO2 Max, or in layman’s terms, the maximum amount of oxygen that you’re able to use during workouts.
With an active GPS signal, this cheap Garmin watch will be able to hold 11 hours of battery life, but you take it out of GPS tracking mode, the watch will be able to keep a charge for over a week. That's pretty impressive since even the newest Apple Watches can only hold a charge for a little over a day.