I am amazed that people will spend a fortune on track, use a quality roadbed, labor to get it straight and then put something substandard on to finish it. Getting the right size granules is as important as the actual color. If saving money on ballast is really important to you how about putting something really cheap down as a base like playground sand and then cover it with a fine layer of good quality ballast? Hot water suggested this to me and I think it just makes a lot of good sense. I'm not trying to make anyone feel bad, but I think this is the wrong place to try to save money.
Art