There is no need to spend a lot of money on fancy envelopes. Handmade envelopes are as nice as almost anything you can buy in a store and cost little to make. If you use paper you already have on hand or make your own recycled paper from junk mail, they don't cost you anything but your time.
Lay a sheet of paper flat on a hard surface with the length facing north and south. Feel free to use any type of paper you have available. Get creative with the paper type. Consider using recycled magazine pages, calendar pages or even a cereal box. You could also use standard copy paper, card stock, scrapbook paper or metallic paper.
Fold the bottom of the sheet up about two-thirds of the way to the top of the paper and fold the remaining paper down over the edge of the first fold to create a flap. Unfold the paper; you should have two large sections that are about the same and one smaller section at the top.
Fold the left and right sides of the paper in toward the center, approximately 1/2 inch to create side margins. Unfold the margins; there should be three creases along each side.
Use scissors to cut out the side margins on both sides of the top and bottom sections of the paper. Leave the center margins intact.
Refold the side margins in the center section and crease the fold. Place a line of glue along each margin and fold the bottom section up, over the side margins. Gently press along the sides of the paper to attach it to the glue. Allow the glue to dry.
Place your letter, card or note inside the envelope. Run a line of glue along the inside of the top flap and fold it down over the back to close the envelope.