It is fun to make your mail more personal by making a envelope for your mail. You can also make a matching envelope for your cards or mail. It is easy, does not take a lot of time and you save money. I use pages of magazines and, patterned paper. It is an easy process and not much is needed. Paper, scissors and glue. There are a lot of templates and devices to make envelopes. I have a scoreboard, but most of the time I eyeball it or match my mail to the paper fold and cut. If the paper is tin, you can also adhere some printer paper on the inside of the front and back of the envelope.
Envelope made using the Martha Stewart scoreboard.
Envelope made using my mail to adjust the size of the envelope.