Where to buy an action camera?
If you like supporting a local economy, walk around to your camera retailer. See what they have. It is always better to speak and see the camera in person. Personally I buy all my cameras online.
It is hard to list all the online stores that sell action cameras. Besides on manufacturers website (most of them have their own stores) lots of retailers have wide variety of cameras. Sites like Amazon and eBay are good starting point.
I regularly update deals on action cameras on this page, so you can check it out as well. Perhaps there is a coupon or a promotion for a camera you picked.