I'd say to get a good dash cam you'd need to spend at least £30. You can definitely get them for less, but the footage quality isn't always great. For an extra tenner, it's worth knowing you can see the reg number or particular details in the event of an accident. The Aukey DR01 is currently £50 on Amazon right now, but we've seen it as low as £38. It's not got many features but the footage quality is very decent, review here: www.amazon.co.uk/AUKEY-Supercapacitor-Dashboard-Re...1

Obviously if you spend more, you'll get better footage quality and features (like GPS, WiFi etc). But if you just want a basic camera, you can find a host of good ones for less than £50 on Amazon. Check out our top ten best dash cams under £50: kit.honestjohn.co.uk/top-tens/top-10-dash-cams-und.../

Alternatively, you can take a look at the reviews of all the dash cams we've tested for a variety of prices: kit.honestjohn.co.uk/category/dash-cams/