You can lay a stone patio yourself. Here's how. Prepare a base of sand or stone dust to provide good drainage in a level surface. Use strings to determine level and to set the boundaries for your design, then set your stones in place. Set them tightly against one another, so you won't have to fill in the gaps between the stones. Tamp firmly with a rubber mallet and then check for level.
For more on patios, consider:
Patio Materials 101
Patio Planning Guide
Patio Design: 7 Popular Materials to Consider