cheap:
100% crisco (altho over here crisco is damn expensive, but i heard that's not the case in the US where supply is abundant?)
40% palm, 20% coconut, 40% canola (our palm and coconut are pretty cheap, but olive is expensive, so canola is an alternative)
personal preference for me:
35% palm, 20% coconut, 21% olive, 20% canola, 4% castor
w/o the castor:
35% palm, 20% coconut, 25% olive, 20% canola
there's a video by soaping101 about making soap using ingredients from the dollar store:
[ame="http://www.youtube.com/watch?v=qWnqXTqZTvU"]http://www.youtube.com/watch?v=qWnqXTqZTvU[/ame]
i reckon it's a decent soap, with clever use of the right additives, you can still pamper your skin
some nice additives you can use: goats milk, cow milk, yoghurt, cream, honey, oatmeal, coffee grounds or poppy seeds for exfoliants, coconut milk, buttermilk, and the list goes on...