Amazon has the Garmin vívoactive 3 Smart Watch w/ Heart Rate Monitor (2017) for $156 with free shipping. Retail price: $300. Features Garmin Pay mobile payment service and wrist-based heart rate.

Has above average Amazon Reviews.

Amazon has the Apple Watch Series 5 GPS 44mm Sport Smart Watch (Silver/White for $404 - $19.01 off at checkout = $384.99 with free shipping. List price: $429. Features always-on Retina display, electrical and optical heart sensors, built-in compass, fall detection, water resistant up to 164 feet.

Has excellent Amazon Reviews.

eBay has the Open-Box Samsung Galaxy 46mm Bluetooth Watch (SM-R800NZSCXAR) for $175 with free shipping. List price: $349. Features fitness tracker, HR monitor, and more activity measurements, 1.3" super AMOLED touchscreen, 802.11n wireless, GPS, Bluetooth 4.2, compatible with iOS and Android devices.

Amazon has the Fitbit Versa 2 Health & Fitness Smartwatch (several colors) for $130 with free shipping. List price: $200. Features always-on display option, heart rate monitor, sleep tracking.

Has good Amazon Reviews.

Amazon Offers Save up to 41% off on Garmin Smart Watches shipping is free on all orders for Prime members.

• Garmin Instinct, Rugged Outdoor Watch with GPS, Features GLONASS and Galileo, Heart Rate Monitoring and 3-axis Compass (Graphite) for $200
• Garmin Venu, GPS Smartwatch with Bright Touchscreen Display, Features Music, Body Energy Monitoring, Animated Workouts, Pulse Ox Sensor and More (Black, 010-02173-11) for $300
• Garmin vívoactive 3, GPS Smartwatch with Contactless Payments and Built-in Sports Apps, White/Rose Gold for $170