1. Go to a yarn shop in your area. (For example, someone who lives in the Washington, D.C., area could go to any of the many fabulous shops in Maryland or Virginia.) Do not, under any circumstances, go to a Hobby Lobby. I will know. If you send me $3 yarn, you will get $3 socks.
2. Buy two skeins of sock-weight yarn (also called fingering weight; the yarn shop ladies will help you). Get two skeins of 400-450 yards per skein or four skeins of 200 yards/skein in your choice of color and material (washable--acrylic or superwash; I refuse to hand-wash socks, and don't want you to, either).
3. Mail me the yarn (remember, that's 800-900 total yards), your shoe size, and some general style preferences (e.g., lacy? ribbed? cabled?). I reserve the right to overrule your style preference if it doesn't match the yarn you sent (e.g., self-striping yarn is best in plain knit stitch, usually still pretty cool in ribbing, and looks downright dumb in fancy-pants lace and cables; ask me how I know).
4. One ball of yarn will be returned to you as a pair of socks.
5. The other ball will stay home with me where I will pet it while giggling maniacally at my own evil genius because I tricked someone into sending me yarn.