UPDATE: The ESTA Fee Has Now Become Law.
The U.S. Senate just passed a bill (with the House expected to shortly do the same) which would add a $10 fee every time a visa waiver person renewed their ESTA (Electronic System for Travel Authorization) registration. If such is the case, then one might as well pay the $131 and get an old-fashioned B-2 (tourist) Visa, valid for ten years.