I had a trainer tell me about using ivory dish soap. Just a squirt in a bucket of warm water. I haven't bought saddle soap since! It's amazing. You must condition your saddle after though since there isn't any conditioner added to it. Passier's lederbasalm is my favorite. (no idea if I spelled that right!)
Yep, the trainer who told me is a grand prix rider who has a tad coffin saddle (which I believe starts off around $5,500). I figured if she used it on that and loved it, i'd try it! It definitely works better then a lot of other saddle soaps out there! And for a fraction of the cost!