I would say 50% of PPL air law material is total c**p.
...
By far the best investment for anyone doing a PPL is the PPL Confuser.
Rubbish!
Best "investment" is time spent learning the material.
This would also save a lot of ridiculous questions which even a pre-solo PPL student
should know the answer to.
A few classics:
How do I file a flight plan? 
Can I fly above cloud with only a PPL and night rating?
Can I use my IMC-rating in France?
Umpteen dozen posts/threads confusing VFR/IFR with VMC/IMC.