Home Depot sells Rebar in 1 ft lengths or you can save $4 and buy a 10ft piece and cut it yourself. Make a "pad" of the concrete bags side by side, front to back, etc. Just keep it one layer deep. When you put down the first bag, stick the piece of rebar into the side about six inches where you will have adjoining bags. When you put the next bags on, you will need to slide the bags onto the rebar as you set them like a shish-kabob. If you do it in place like this, just try to put some water on the bags before the first rain to get it to start setting. If it rains real hard and the paper washes off to fast, it doesn't look nearly as nice. As long as you keep the bags relatively tight together, you shouldn't need to worry about them getting washed out underneath. If 80lb bags of concrete are too heavy, you can get 40lb bags for about 50 cents less, but you will end up spending twice as much because they are much smaller.
