I saw this idea on Pinterest and loved it. Its super easy, and the envelopes are just charming.
1. Choose a sheet of paper.
2. Open up an envelope to use as a pattern and trace around the pattern, and cut it out.
3. Score the fold lines with scissors and a ruler.
4. Fold along the scored fold lines.
5. Use double stick tape to seal the two sides of the envelope. You can add more to use later when sealing the top.
These envelopes are a large card size and used a sheet of 12 by 12 scrapbook paper, these were by Mirabella.
A normal correspondence envelope uses a sheet of printer paper, making it possible to use cool stuff off the Internet for paper. The three envelopes above are made from a page of a French newspaper, a map of Paris and some handwritten script, all images I found on Graphics Fairy.
These envelopes are made from vintage wrapping paper.
Other materials that would make great envelopes, are old newspapers, sheet music, pages from an atlas ... the possibilities are endless.
And look how great they all look stowed in an old desk's cubby
Uses for the fancy envelopes can include special correspondence, of course. You can also make corresponding cards to match. Mine will likely end up being used in smash books to hold those extra fun small details, that are so fun to handle, like tickets stubs, love notes, railroad passes, receipts and small pictures.