While I admire your intentions, I think $2 might be a bit low to be able to shoot for if you don't have huge manufacturing capabilities to take advantage of economy of scale. If you intend on selling them for that price I suspect you'll pretty much be working for free. The ideal thing (IMO) would be to barter, make soap and trade it to people for things they make in return. That's one of the things I do with the beer I make.
I think the $5 to $6 price range is eminently affordable for someone even on a low income, especially considering you'd pay a lot more than that for an equivalent amount of spray foam. The mamabear and arizona goat milk soaps come in around that price and although I've not tried them (yet, although I will) I hear they both give superb shaves.
You don't *have* to go out and spend $15 on a round of soap, there's good alternatives for a third of that, even without choosing williams et al. However, I'm fascinated by the soap making process and, like you, will probably be experimenting with making some batches just for the heck of it to see if I can do it althought I don't think I'll stop buying it either. I hope you'll share your successes (and failures) with us so we can learn from your experiences.
-- Gary F.