We are fellow users here on these forums, we won't know what the charges are for.
Does anything show on your purchase history : http://support.apple.com/kb/HT2727 ?
Do you have any auto-renewing subscriptions : http://support.apple.com/kb/HT4098 ?
If nothing shows on your purchase history, or they do but you didn't make them and nobody else has access to your account or devices and may have made them, then try contacting iTunes Support and see if they can help : http://www.apple.com/support/itunes/contact/ - click on Contact iTunes Store Support on the right-hand side of the page