Natty's skin reacts to the fragrances in the major brands (johnsons, huggies etc). We use GAIA natural baby wash. We buy it with the groceries and it costs about $10 (exxy, but you don't need to use much so it lasts a good while.) It doesn't have sodium laureth sulphate in it (that frothing agent - Natty seems to be sensitive to that one).
Beware though - before you start buying up big, know that if you have friends and family who will give gifts (and even people you don't think will give you gifts - they WILL LOL!) you will likely get a truckload of toiletries! So don't go all out IYKWIM.