Why not BRIBE the Dursleys, for heavens sake?

[Casey]

No: HPFGUIDX 123277


Lupinlore suggests:
 
If he doesn't want to use money, its hard to imagine he could not 
use magic to deliver material advantages to the Dursleys. Yes, it is 
a violation of Wizarding Law.  But it's impossible to believe 
Dumbledore couldn't have pulled that bit of larceny off.

Casey:

When I gave it thought, I felt that it's because Harry has to live 
with blood relatives, not board there, as paying would make it. Same 
with the presents. As small and senseless as they are, a gift must 
be given to keep those family ties, well...tied.