Zagall offers this Mini DisplayPort and USB Audio Male to HDMI Female Adapter for $36.70. Coupon code “25BACKTOSCHOOL” drops it to $27.52. With $3.53 for shipping, that’s the lowest total price we could find for such an adapter by just under a buck. This device integrates the Mini DisplayPort video source and USB audio source of the MacBook into HDMI output. It supports resolutions up to 1080p.