I can't believe nobody has pointed you to
Spanking Dollars. They have eight or nine excellent pure spanking sites including the venerable
Girls Boarding School.
I second the recommendation for
Cybernet Bucks -- their Whipped Asses site makes good money for me.
I also do very well with
GUBA: The Gigantic Usene Binary Archive by pointing my spanking traffic to
alt.binaries.pictures.erotica.spanking.