I recently purchased an SJ7 Star by SJCAM for around £140 ish. It's a 4K camera and it's pretty good. Seen lots of video on youtube before I made my purchase. Few year back i was going to purchase the SJ4000 (around £100 at that time, £50 ish now), again by SJCAM. They seems to be pretty good too but on at 1080P. Micro SD card will cost around £30-£60 depending on the speed of the card needed. 1080p you can get away with slower card, but for 4K you'll need a fast read and write card.