The most basic moisturizer there is would be an oil. Popular oils which tend to not clog pores include mineral, sunflower, safflower, hemp, jojoba. Other good ones that I've personally tried are argan, tea tree oil (always dilute before using), coconut (highly comedogenic -- use with caution).
That said, oils are only emollients, and you probably want a humectant, too. Glycerin is the most popular and common humectant. You can find plain glycerin in all sorts of places -- the drug store, skin care stores, and even grocery stores (it's also used in thickening icing, haha).
Honey is a both an emollient and a humectant, but has the downside of being terribly sticky. Be sure to get raw if you can, unpasteurized if you can't.
It also wouldn't be too hard to emulate the majority of Lush's formulas, subtracting the synthetic fragrances and etc they add in. A lot less expensive, too.
/emoticons/
