live plex transcoding
If you need this, the most cost-efficient way is probably to get an Intel CPU with an integrated GPU that supports QuickSync (all recent ones do) and pay for the lifetime Plex Pass. In the long run, it's cheaper than getting a beefier CPU, let alone a dedicated GPU, just for transcoding.
Here is a thread with 4th July deals. On that forum you can often find deals for cheap, low-spec VPS.