Ask if you can receive a free gym membership through the Silver Sneakers program that comes with some health care programs for seniors. Programs may offer memberships at Ys, commercial gyms, or senior centers. Programs differ nationwide & consider you a "senior" at different ages.
Luckily my Silver Sneakers program is good at a very new & well-equipped Y which is only 12 minutes from home. Things might be different in other areas, but my Y is less crowded in the late morning or early afternoon because many people stop there on the way to or from work..