During my maternal shopping experience I noticed nursing covers seem to cost anywhere from twenty to fifty dollars a piece with limited coverage and conspicuous patterns. Not my cup of tea, but I found a pattern for a full coverage cover that is simple enough for even the most novice seamstress. I paid about $1.25 for the thread and about $6.00 for the fabric. You can even sew this up by hand in a few minutes if you don't have a machine.
I would suggest NOT using 100% cotton knit fabric like I did because it tends to cling to itself and my cotton shirt. Other than that, it is very comfortable, and I feel secure that no one will be getting a peek at my baby's mealtimes. I did leave mine long since I seem to be taller and need more coverage than the girl in the tutorial. Although upon examining this picture I may trim a good four inches off the bottom.