A good easy and cheap exercise is walking, not just occasionally but regularly every day. 30 minutes a day or if that is too much then 10 minutes 3 times a day.
With a little motivation, this is easily achieved. Find a friend to do with, park the car a block from your destination, and walk. Take the stairs instead of the elevator, at least one floor. Whatever you do make it an integral part of you daily living.
I am not selling here anything other than an idea, but I am doing it and see results and want to share it with anybody who listens.