Ocean Technology via Amazon offers the
Unitek DisplayPort to HDMI 4K UHD Adapter Cable with Audio in White, model no. Y-6332, for $7.99. Coupon code "YPQCKDF4" cuts that to
$3.99. Plus, Prime members bag
free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $8.15.) That's $6 under the lowest total price we could find for a similar item elsewhere. It supports video resolutions up to 3840x2160 (4K, 2160p) and 7.1-channel surround audio and features gold-plated connectors.