We got postcards for save the dates, and one of the draws was that postcards cost less to mail (35 cents as opposed to 49 for a standard letter, which adds up when you're mailing a lot)... but now as I'm looking for stamps the only ones I can find are either some "coastal bird" set offered by USPS or 35 cent stamps by Zazzle that you have to pay over a dollar a piece for since they're custom. Any advice on how to keep postage cute on postcards without paying extra?