Not the best deal we've seen ($449), but still a good price at basically $510. Bought it at this price as I'm wanting it quite soon.
This monitor checks a few boxes with it being 3440x1440 res, 100Hz, Freesync, VESA mount.
Read more about it in other posts here: https://www.ozbargain.com.au/product/kogan-kamn341fqula
Video review: https://www.youtube.com/watch?v=YuHbS9WawV4
VESA Wall Mount Pattern 100 x 100
Weight With Stand: 7.7kg | Without Stand: 6.6kg
Without Stand 815 x 363.8 x 96.7mm
With Stand 815 x 437.4 x 285.7mm
Brightness Typical: 250cd/m² | Minimum: 180cd/m²
Colour Depth 16.7M
Contrast Ratio 3000:1
Freesync Range 48 - 100 (HDMI and DP)
Native Aspect Ratio 21:9
Panel Manufacturer Samsung
Refresh Rate 100Hz
Resolution 3440 x 1440
Response Time Response Time: 16ms | OD 7.8msms
Viewing Angle 178° / 178°
Power Consumption 60W
Standby Consumption < 0.5W
Manufacturer Warranty 1 Year
It's also $577 + delivery on their eBay store, so if a good eBay deal comes around, it may get below $500.