Whether or not bulk loading saves money, depends on the film. You just have to do the math. Last time I did, I decided that TMAX was worth bulk loading.
Making short rolls because you find it hard to shoot a whole roll doesn't make sense to me. It makes more sense just to use full rolls, develop what you have exposed and leave the rest in the camera. When I have a half a roll I want to develop, I just go in the darkroom or changing bag, pop the back open without rewinding, tear the film off and pull out the exposed strip, and load it on a reel. Later, in the light, I just trim the leader left in the camera and reload the camera.
That too makes sense. A little more cumbersome but more economical nonetheless.