Not the lowest price its been for the Samsung Gear S3 Frontier - but haven't seen its price <$300 from AU stores lately.
MANUFACTURER SPECS
Rugged Looks, Bold Performance
Always On 1.3" Super AMOLED Display
Compatible with Standard 22 mm Bands
Bluetooth/WiFi/NFC, GPS, Glonass
Built-In Speaker
Infra: Bluetooth Only
ANT+: No
USB Version: N/A
Location Technology: GPS, Glonass
Wi-Fi: 802.11 b/g/n 2.4GHz
NFC: Yes
Bluetooth Version: Bluetooth v4.2
Bluetooth Profiles: A2DP, AVRCP, HFP, HSP
OS: Tizen
Technology (Main Display): Super AMOLED
Size (Main Display): 1.3" (32.9mm)
Resolution (Main Display): 360 x 360
Color Depth (Main Display): 16M
CPU Speed: 1GHz
CPU Type: Dual-Core
RAM Size (GB): 0.75 GB
ROM Size (GB): 4 GB
Available Memory (GB): 1.5 GB
Sensors: Accelerometer, Barometer, Gyro Sensor, HR Sensor, Light Sensor
Standard Battery Capacity: 380mAh
Removable: No
Typical Usage Time: 3-4 Days
Audio Playing Format: MP3, M4A, 3GA, AAC, OGG, OGA, WAV, WMA, AMR, AWB
S-Voice: Yes
Additional Features: Messages, Phone, Contacts, S Health, Weather, Music Player, S Voice, Settings, Reminders, Alti/Barometer, Schedule, Alarm, World Clock, News Briefing, Gallery, Find My Phone, Email, Monster Vampire
https://www.ebay.com.au/itm/Samsung-Galaxy-Gear-S3-frontier-…
$281.59 with PSAVEIT for plus members. Have no idea if it's Aus stock - (Need Aus Stock for Samsung Pay)
Or… https://www.ebay.com.au/itm/Samsung-Gear-R760-S3-Frontier-Bl…
$258.91 with P10LESS
Bing lee will no doubt give you a better buying experience and security over the two above. But they are both Plus sellers, so easy returns if you're not happy etc.