Each year I buy half price Christmas paper after the holiday at Michaels so I'm ready for the following year. I order my cards from Costco, which are 6 x 7.5 inch picture cards.
First I start with a piece of 12 x 12 card stock (or wrapping paper, or whatever you want).
Next fold in the sides of the card stock. Be sure to hold the cardboard tightly so it doesn't move when folding.
Snip the corner of the flap that will fold up and add some glue.
Now it is all set for your card.
Here are a couple of my other envys for my friends and family this year.
To add addresses I print them out on the Avery address labels. They show up nicely on the paper and much easier to keep track of them each year. I've never had a problem with the post office delivering the cards. They take one stamp and haven't had any returned to me requiring more postage - hope that holds true for this year!!
Thanks for looking.