I buy the miso paste from whole foods. Ours have three different versions. I buy the Miso instant soup packs from our oriental store. I don't know the brand I love b/c its in japanese, but I just asked the owner what her favorite was and she showed me. I bought a couple of brands just to experiment, but she was right. The one she picked out was the best. I do add extra water to it in case the sodium level is higher than we are supposed to consume. I remember reading (I think in TKD) that the miso soup at japanese restaurants was loaded with sodium so it wasn't our best choice. Good Luck!
My Whole Foods carries two brands. Westbrae Natural comes in little tubs and is in the refrigerated section near the Veganese. Eden comes in bags and are in the Asian area. Be careful of the dry miso soup mixes. Most contain fish in the broth. Miso soup in Japanese restaurants usually contains fish too.