There are many options for materials to build retaining walls in Phoenix Arizona. If you have a low budget, you may want to choose natural stone, which is relatively inexpensive. Natural stone can crack or chip if it is used on a slope. Concrete and steel reinforced blocks are the second choice. Even reinforced block walls are more expensive than its cheaper counterpart, homeowners often choose it when they are planning a retaining wall. It may be worth the extra expense if you want to build a Phoenix retaining wall that will last decades.