It was around $160-$180. Transcoding is generally needed when a device doesn't support the specific file. It'll be converted to a playable format on the fly. Like if the device doesn't support HDR. Or going from 4k to 1080p.

As much as I love my Shield Pro, I just recently had to switch to an actual dedicated device for streaming. The shield pro is showing its age and could not keep up with transcoding and I had nothing but issues with the server being available. I switched to a pretty cheap mini pc with an Intel N100 (Intel sync allows for quick and power efficient transcoding). It's been night and day in terms of performance.