Flushing brake system at a Toyota dealer is cheaper for sure. You only need to shop around. It cost me $140 Canadian a few months ago (~US$100).
I explicitly inquired about using the Techstream software for actuating the ABS system and I was told that it doesn't require such thing.

Check Toytota dealers in your area (and negotiate the price.) Alternatively, a trust worthy mechanic is the answer for such simple yet crucial job.

Here's my post about my experience with the brake fluid flush:
https://www.clublexus.com/forums/rx-...ush-today.html