If joining a gym is not in your budget or simply not your preference, it is entirely possible to put together a home gym with a modest financial and space expenditure. Toning your butt requires you to do exercises that both isolate the gluteal muscles and work the entire lower body as a unit, and plenty of equipment exists to help you see results.
Treadmill or Stair-climber
If you build your gluteal muscles without getting rid of the fat, your butt will just get bigger. Cardio exercise is the key to burning fat, but you can optimize it to work your butt muscles at the same time for a two-in-one workout. Incline is the important factor -- walking or jogging on a treadmill or using a stair-climber both work the entire lower body with an emphasis on the glutes as you work to move your body weight up the incline. If a new machine is not within your budget, used or refurbished machines are widely available at deep discounts. If you don't have space for a machine, walking on hilly terrain or jogging up and down a staircase can provide a similar workout.
Resistance bands are a good way to work up to weights, but they are an experience unto themselves. Unlike weights, which must be held in your hand, resistance bands can attach to any part of your body. This allows you to add resistance to exercises -- for adductors and abductors -- that work your butt from the sides. They also provide support for exercises like lunges and deadlifts. Resistance bands provide a linear resistance, which means the farther away from the anchor you get, the harder the exercise is, even within a single repetition. Choose a medium-resistance band to start, and begin your exercise farther from the anchor as you progress.
Many people don't think weights are necessary to a butt workout, but resistance is vital to getting results from butt-lifting exercises like deadlifts, lunges and squats. You can hold a dumbbell in each hand or use both hands to hold a barbell, but increasing the load beyond your own body weight is the only way you'll get the results you want. Ankle weights are another good option to add resistance to leg lifts and fire hydrants, which give you the indentations in the sides of your butt. Weights can be pricey, so don't worry about buying a whole set at once. Start with what you can use now, and then buy heavier weights as you need them.
A step is a handy tool for butt toning for the same reason as the stair-climber. Each time you lift your body weight, the power comes from your butt. Adding a step to a circuit workout can boost your progress, and using the step during other workouts adds to your butt-firming results. For example, step on and off the step as you do bicep curls during arm workouts. The step won't detract from the curls, but it will add a lower-body element that can speed your progress. If you have a staircase in your home, you can use the bottom step instead of a fitness step.
Balance balls are known to be stretching aids, but many exercises can be done on the ball to add a stability factor. When you must work to stay upright during an exercise, your body calls smaller support muscles into play. These muscles don't get much work during a normal workout because you maintain a posture that is comfortable for you. But the first time to try reverse extensions or hamstring curls on the ball, the lack of firm footing will show you butt muscles you never knew you had. Balance balls are fairly inexpensive and deflate for storage when not in use.