I'm sending a few invitations overseas. Do I put return postage on the response envelopes, since other countries use different postage?
If you really are sending only a few overseas invites, ask at the post office when you go to mail the invitations -- perhaps they have overseas postage you can include. If not, it's not horrible to send those response cards without postage; your guests will likely just slap their own stamps on them and mail them back without another thought. If you feel uneasy and your overseas guests have online access, include a note that says "Feel free to email us with your response!" and include your email address.
See More: Wedding Invitations + Wedding Stationery , Wedding Invitations , Save-the-Date Cards