You can eliminate RSVP cards, if you caterer does not ask you for a specific minimum limit. By eliminating the extra bulk of the cards, you can save the costs involved in the cards, as well as the postage.
Always try to purchase the envelopes that are of standard size. If you use large-size envelopes, then you will have to pay for extra postage fee.
When it comes to sending mails, the weight plays a key role in setting the postage fee value. The heavier the postage will be, the higher the postage fee will be charged from you. So, you should try to use light-weight paper when creating your invitation cards. You can also try to minimise the number of sheets per invitation. For instance, you can print the map at the back of the hotel address card.
You can also deliver the invitations by hand, if your relatives live near your residence. This way, you will be able to save the postage fee entirely. In addition to that, it will also leave a positive impact on your relatives that you personally went to them to invite them to your wedding ceremony.
You can also use online tools to send RSVP cards. You can visit different RSVP website, which allow you to send the wedding invitations without spending a time. Even if any website charges you, it will be far less than to send invitations through a mail service. Moreover, you will be able to add as many pages as you can, including all the information related the hotel, dinner timings, map and any other important wedding information you want to add.
You can also use a social networking website, such as Facebook, to send invitations. You can just create a new event and send invitations to the people in your friend list. You can also add email addresses of people who are not in your friend list.