Messagenet Fax VoIP SMS for a free italian did voip number.
sipgate.de - Ihr kostenloser Internet-Telefonanschluss. for a german number, only 018x number available for outside germany.
Budget Phone Company your shortcut to VOIP for a dutch number cost 10 euro per year.
did.voip.les.net VoIP DID us did number
You will find more examples online for paid did / vopi numbers.
No you will not get charged. When you call the number and pbxes recognises your caller id, you will receive a busy tone, this means you will not pay anything to trigger the callback.