Why make padded envelopes with bubble wrap made out of plastic? Why not pad envelopes with paper? Here's how I did it:
Make an envelope out of thick paper, like a paper bag from the supermarket, or use a pre-made one lying around the house.
I used this template from Country Living and modified it to my dimensions, but any will do.
Tear out and crumple old magazines, paper, newspaper, etc. I used a page and a half here. Tape the corners and the sides of the paper on the envelope making sure the paper has lots of slack to pad what ever you put inside. When you add padding to the bottom flap, leave space in the margin or you won't be able to glue the envelope together.
After gluing the flaps together (I did it with a glue stick) and making sure to add lots of pressure to make the glue stick, it's done! A padded envelope made with scraps lying around the house.