The Pathmate molds beat hand-laid pavers six ways from Sunday. If you can scrape your site to undisturbed soil and have no drainage issues, you can cast stepping stones without going to the gravel and sand method. The wet mix absorbs irregularities--if the mold is level, the stones will be level. Each cast sets enough for the mold to be removed by the time you've mixed the next 60-pound bag. The only limit is set by the number of bags your vehicle can haul or how many your old, retired back can manage. The plastic material in the molds is the same stuff used for shipping pallets, so you'll have to work hard to damage it. Works good for me!
You can get the mold from Amazon.