Ursula, if you do a search for "garden edging" using the box in the upper left, you will see that Hometalk members have used everything from rocks and bottles to plates and bicycle wheels for gardening edging. I'm sure you'll find some inspiration there.
Ursula R . I was in the same boat as you last summer I wanted something unique and on the cheap. I bought a 25ft piece of black plastic accordion style tubing used for drainage. I dug about 5 inches deep laid the tubing in and filled around the edges with gravel. I also sprayed grass/weed killer on the gravel to keep the weeds from popping up. To secure the tubing I bought long galvanized spikes and drove them right through the tubing into the ground about every 6ft. I did them that close since I curved the tubing and its on a grade. I put small solar lights along the inside edge of the tubing. I even got compliments from a neighbor who is a landscaper :)
The attached picture is not my yard but it will give you an idea of what it looks like,
thanks, I'm in the process of making a butterfly shaped flower bed in the back yard and as I finish I will put some pictures up.
i am going to try using empty tin cans and plant half way down and use as a border. CAN paint or use as is