I went 44 SPSD, 20 DET, and 11 CRT simply because I wasn't willing to dish out any further for DET materia, especially not for a Job that isn't my main.
Spellspeed, however, thanks to being garbage for all casters but BLM, is fairly affordable even at tier IV. The whole thing cost about 2.6 mil
Edit: The "garbage for others" part looks like it could change with 3.0, but for the moment, yeah....