You can make microwave popcorn yourself, using a paper lunch bag. Just cover the bottom with kernels such as Orville Redenbacher's. Microwave for about 1 minute 30 seconds (your microwave will vary so practice with the timing). Take it out, being careful of the steam when you open it. If you need salt, you can spray inside the bag with Pam, then the salt will stick. Gourmet popcorn for pennies!
Editor's Note: This tip was originally submitted in response to 10 Huge Retail Rip-Offs. We felt this instructional video would be helpful in demonstrating how to do this at home (note: you will see an ad at the beginning that will last about 15-30 seconds and you may hear part of the instructional video in the background during the ad; when the ad finishes, the video starts from the beginning so you won't miss any of it):