The Bar Jump is the "core" of agility, used the most in competitions. For simple practice it is fine to have one or two jumps. For more challenging exercises (such as rows and pivot squares) it is ideal to have four jumps.more info....
If you are starting off in agility and wonder which jumps to start with, we suggest the basic "bar" jump (either the Economy-Adjustable Jump or the Competition one listed next). Second, a Tire Jump adds a colorful and different jump to your selection. For more challenging work, a Triple Jump, Broad Jump and Panel Jump are also good (especially for those also involved in obedience competitions).