Popular brands include T & T Products (about 1200? L$ for the basic version, plus more for various plugins and accessories, a version with random stimulation will probably set you back about 1700), KaS also do a belt, that has fewer features but is a bit cheaper.
Oh and the maids uniforms... Try Kcreations on the Marketplace, or KaS (The KaS looks a bit nicer, and the shine/textures match their strapped ballet boots, strapped gloves, posture collars etc).
Thanks, would look for.