Well if you want video for just incident protection and radar and a rear light on your bike, you could get the Cycliq gen 3 plus the Varia RVR315 and slide in about $20 - $30 less than the current $399 for the Varia RCT715. But then the realestate on the back of your seatpost will be competing with your seat bag.
If you only want an action cam, this is not the product for you. If you only want a rear light and rear camera this is also still not the product for you.