I prepare my birthday packages the same way as sewbizgirl I often just make a card on regular copy paper so it is thinner and then I spend the extra money to buy a box of large silver heavy card envelopes at Walmart. They are very good quality so shouldn't rip. I have had some packages come that the envelope had been thin quality and it has been ripped open on some edges from the handling in the mail. I think the envelopes only cost around 75cents to mail. My Post Office has a stamp that is that price. I go to the Post office when the swap starts and buy the number of stampls I need for the whole year for the swap.