Pancky/ZDNET Follow ZDNET:  Add us as a preferred source  on Google. Using a metal detector as a hobby has seen a resurgence thanks to social media. And if you've been wanting to get started hunting down old coins and knick-knacks, the Pancky starter bundle is the perfect option. It includes everything you need to kickstart your new hobby or rediscover an old interest. And right now at Amazon, you can save 35%, bringing the price to just $110. Also: Our readers can't stop buying these gadgets The metal detector itself features a water-resistant coil, so you can confidently comb river and creek banks, beaches, and other watery areas without fear of damaging your detector.…