Some more low suds options....
The Sun Detergent in the big bucket is also really low sudsing. It's not as potent as the Sears or the Kirkland, but it works well enough on everyday soil. Another one that works well is FMV (Kroger/Fred Meyer) in the bucket, and Good Day detergent in the bucket from Albertson's. A final one that's good and low suds is Next to Godliness from Trader Joe's (if you have one).
Lately, I've been grating up a 4-5 oz bar of soap, melting that in some hot water on the stove, and then mixing 1 cup washing soda and 1/2 cup of borax in a gallon of hot water. I pour the melted soap mixture into the borax/soda solution, stir well, and ladle it into containers and let it cool.
That mix produces minimal suds, yet seems to hold the soil in suspension. About 1/2 to 3/4 cup per load is enough to make the water feel "slick" in a top loader (generally enough for adequate cleaning). It's incredibly cheap to make, and doesn't give anyone a rash (big plus in a family of people with sensitive skin). I use a little vinegar in the rinse to get the last of the residue out.
Any of the above produce minimal suds in our Frigidaire top-loader (Franklin transmission with a straight vane agitator that suds locks on medium or low fill with almost anything) and the Maytag wringer, yet seem to get the clothes clean.
Hope this helps!
Mike