I think perhaps for a kid, before they start producing excess oil in puberty, that the most important thing is to keep their skin clean. Do you have anything like Cetaphil in the UK? That's really gentle, we used that in Riv's bath when he was newborn, and I used it when I was a teenager to clean my face.
The other one would be that Ego stuff. They're both pretty cheap too, but very gentle yet effective!

Or perhaps a vegemite mask? River seems to take that option most days...