I'd also suggest that she earn the money to replace it. This is a HARD lesson but it's an essential one. She'll learn much more than just not to misplace it again; she will learn the value of saving and waiting.
Background: I have a 15-yr-old son who has an Ipod Touch that he takes very good care of. It was his only big Christmas present. He lost a more basic Ipod about two years ago, and decided that it was not worth it to him to spend the money on another. (And BTW he did have enough money to buy another if he wanted to.) I have a 13-yr-old daughter who takes pretty good care of her MP3 player, though she does "forget" it in the car from time to time. I also have a 17-yr-old son who does not own any of these devices because we know he would not take proper care of them. He's just trashed his last pocket radio, because he didn't take it OUT of his pocket before putting his shorts in the wash. This sort of thing happens to him all the time, as he still has not learned the lesson. So we never give him any electronics costing more than about $25-$30. Replacements he has to buy on his own.
As a parent, you will get to watch and see, when the replacement Ipod eventually comes, whether your daughter will be one who can learn to care for her things... or not. And you'll be able to figure out what gifts to buy, or not to buy, for her, based upon what you learn about her.
(Been there, done that...)