Good idea, we always suggest dash cams for that exact reason. It's dependent on your budget and what you want, i.e if you want a front and rear dash cam, if you want something that will record while you're parked, something that will notify you of speed cameras, etc. The most important thing to look out for is footage quality (don't get anything that records at less than 1080P @ 30fps). Amazon reviews generally let you know how reliable the dash cams are, but it's worth figuring out if you need a dash cam that has GPS because some insurers want to be able to review things like speed and location if you submit footage after a collision. Although, if it's a clear case of someone hitting you, then this isn't really necessary. It's more to check that you weren't driving dangerously before an incident occurred. Our advice would be to get the YI Smart if you're after something on a budget (it's £50). In terms of value for money, we think it's the best option: kit.honestjohn.co.uk/reviews/review-yi-smart-dash-.../

If you want to record what's going on behind you, the Nextbase 512GW and rear cam are a good option: kit.honestjohn.co.uk/reviews/review-nextbase-512gw.../. The Garmin 55 is about £115, but it is an excellent dash cam: kit.honestjohn.co.uk/reviews/review-garmin-55/. You can get something very budget (like the Lana Blue), but you obviously get what you pay for: kit.honestjohn.co.uk/reviews/lanka-blue-dash-cam/