In this economic climate, even the tooth fairy’s savings have taken a beating. A recent Visa Inc. survey found that, in comparison with last year, kids today are getting an average of 40 cents less per tooth. Nationally, the value of a tooth has fallen from $3 to $2.60. Ten percent of children get no money at all, whereas only 6 percent of kids last year got zilch for a lost tooth. One curveball in the survey: The tooth fairy has become more generous in the West, where the average reward per tooth is $2.80, in comparison with last year’s $2.70.