These machines may work for rehabilitation purposes, however there is no great benefit in exercising with these than there is just doing cardiovascular exercise combined with strength training.
Swimming, cycling, walking, running, body and free weight training, mostly inexpensive and endless.
My advice would be to invest in some one on one sessions with a Personal Trainer who can provide you with a workout plan appropriate to you, once you have the knowledge, you then have the power to know how to train yourself properly without the need for these gadgets that end up as a clothes horse in the spare room!