Pro Gym Supply - New & Used Gym Equipment for Your Facility or Home. Pro Gym Supply offers the largest selection of used gym equipment. Call us today (800) 504-6068 to buy used fitness equipment or browse our inventory of used exercise equipment like treadmills, steppers, ellipticals, spin bikes, and strength equipment.. used gym equipment, used fitness equipment, used exercise equipment, treadmills, steppers, ellipticals, steppers, spin bikes, strength equipment, selectorized, free weights, plate loaded, benches, racks, smith machines, life fitness, precor, cybex, nautilus, matrix fitness, true fitness, hammer strength, stairmaster, technogym, star trac, hoist fitness, freemotion