"A cast concrete paver is usually going to be the biggest bang for your buck," says Sivgalls. "It's strong, easily customizable, and comes in great colors and textures."
Whether you opt for a cast concrete paver, or a more natural stone, you'll want to make sure that the paver you choose is thick enough and heavy enough that it can be walked on without getting damaged. But, you also want to make sure it's not too heavy, so you can lift it up and place it where it needs to go.