Mailing approaches

I'm hoping to get the invitations out on July 1. But, still, there's the problem with the stamps. Maybe, however, it's not a problem. If 2 oz. now cost $.58 (why did they DECREASE this amount by $.5 when the increased all the other mailing rates?), I can use my wedding $.63 for the invitations (overpaying by $.04 per invite) and then save the $.39 wedding stamps for the RSVP postcards (and overpay postage by $.13 per card). All in all, it's a waste of only a few dollars and my aesthetics will still be intact. PHEW!