Adding backup camera to 2008 Ford Edge

Wondering if anyone here has any experience or advice in adding a backup camera to a 2008 Ford Edge LTD? Our daughter is getting one and she really needs a back-up camera. I'm actually surprised that a backup camera doesn't come on a LTD model but oh well. Is there a simple and easy way to add a backup camera that WILL work with the existing SYNC system (so she can see it on the monitor)? Hard wired or is a wireless backup camera better? Our daughter works as a teacher's aid in a private school so she doesn't have a lot of money to buy an expensive camera so an inexpensive solution is what we're looking for. Any recommendations? As always, thanks in advance to all who offer help and advice