badatusernames
Omono
I have been to both of those places and have purchased trees from them that were on the higher end ( and maybe that's part of another discussion on what newbies should expect from "pre-bonsai" and what they should expect to pay for them.
Yeah, that's the real challenge. That tree I posted came rough and unshaped, so there's still an element of following its development, but I was told it took 20+ years to grow by someone who trained in Japan specifically to learn to grow material for bonsai.
So the investment of the training, the years of growing, etc - it ultimately adds up to something that isn't cheap. And the less expensive material tends to be younger, thinner, what have you.
I don't know enough about the non-bonsai nurseries in the area, but finding landscape material would probably be a good / cheaper way of approaching this. I just don't know who has junipers or black pines. If you find somewhere, I'd love to know about it. But due to the amount of time it takes to grow those, as well, I would be curious as to just how much cheaper they really are.