Economists are fairly unanimous about one element of human behavior. When prices of any product are raised, demand tends to drop. The salient exception is "luxury" goods, where higher prices sometimes stimulate demand. But early evidence suggests that consumers believe 99 cents is the "right" price for a single song.
Last week was the first week of iTunes’s new, steeper pricing on some tracks, and consumers voted with their wallets, according to Billboard. Sales figures from iTunes show that tracks that now sell for $1.29, up from $0.99, sold 12.5 percent fewer units than during the previous week, while tracks whose prices were unchanged sold 10 percent more than the week before.
Overall revenue was up three percent during the week, so it might not be possible to blame the "economy" for the changes. It appears that unit sales for the top-100 songs were up for the week.