Bekah, I don't know where you are, but around my home, washing soda is in the laundry aisle of most grocery stores (by the borax, conveniently enough).
I started making the liquid version of this soap a few months ago, before the baby came. I was really pleased with its cleaning power in our semi-hard water...if you had soft water, you might cut out some of the borax. Since we started washing diapers daily (girl goes through about 30 a day, seriously) we've saved a lot of money already and will save a ton by the time diapers are done for.
Also, to note, our washer is a front-loading HE washer. I debated for a while as to whether the soap would be good for the HE washer, but decided to try it, since it doesn't contain any sudsing agents except the bit that might be in the Fels Naptha, and sudsing agents are what's missing from HE detergents. I've since decided that this stuff hardly sudses at ALL, and is probably great for the HE washer.
And, finally, I find I itch less now that I'm not using detergent to wash my clothing. I used to be a very itchy person--not rashy or anything, just itchy--and now, well, I'm not!
Oh, and maybe she just isn't rash-prone, who knows, but we've had no baby-butt problems around here, which is another thing I was on the lookout for.
