For some people the cost of a home gym is unrealistic and just too much usable space taken up by heavy weights and racks. With machines, racks, barbells, dumbbells, and kettlebells that could all be priced within $150-$1500 depending on the equipment a home gym is unrealistic to most. However, if one is fortunate enough to have even some of that equipment (I personally have interchangeable dumbbells that go up to 55 lbs. and down to 5 lbs. as well as a bench but no squat rack though) they can be used to get a quality pump at home and feel almost like walking out of a gym.
If money is tight and you just cannot seem to get equipment in your house do not worry! (Refer to article on body weight fitness) Body weight exercises can train functional stability and movement better than using equipment. Body weight exercises allow you to train your spatial recognition of the body in space, as well as, functional movements beneficial to joint and tendon stability. Exercises like push-ups, dips, squats/jump squats, lunges, running in place, etc., are all relatively stress free exercises on the joints as compared to lifting with weights. With all exercise, form is most important. (For form reference view Ace Fitnesses top 25 at home)