Nextbase 112 Dashcam comes along with SD Card and Carry Case. It is the cheapest I can find. I know it's only 720p cam and only 120 degree view angle but a carry case itself with sd card costs £20 in Halfrauds.
Few words about what this devil thing can do:
With a 120° wide angle view and 720p high-definition recording, the Nextbase 112 dash cam records every moment of your journey and also helps provide you with instant evidence to prove an accident wasn’t your fault. It comes with an innovative Click & Go powered magnetic mount that uses magnets and powered touch points to allow the camera to be free from wires. For convenience, a special loop-recording feature prevents the recording from stopping once the SD memory card is full. Also, SOS data protection stops the impact or event from being deleted, while a file locking system stores any footage you might want to view again.
The Nextbase 112 dash cam supports SDHC and SDXC Micro SD cards up to 32GB, and is powered by a rechargeable lithium-ion battery with up to 30 minutes backup in the event of an accident. It can easily be installed with the 4m long 12V power cable and can also be hardwired in.