"Snazzy what on earth is this"
These are gingko and wisteria seedlings that I picked up from my bonsai club! They were like a buck each and it's pretty tough to find seedlings for them in my area. They were sold bare-root, which means no soil or anything on them, just kept moist in wet paper towels. So I put them in some pots with open-grain bonsai soil. I'm going to keep them in my garage until they start to bud out and we get above freezing temps, at which point I'll do some repotting and move them outside.
In bonsai you have time and opportunity vs money. Not every seedling works out, no matter what techniques you use sometimes they just don't grow in a way suitable for bonsai cultivation. Or they die prematurely! And for the ones that do work out, it might be five years before it grows enough to even be worth performing bonsai techniques. And even then you will have years and years of refinement before it's show-worthy.
Alternatively, you can pay a bunch of money ($500+) to get a tree that looks good right now.
Seedlings represent a good investment if you buy them in bulk and you know you have time to spend on them. A lot of people at my local club didn't get into it until their 60s, so for them, it legitimately might not be worth the effort to bother with seedlings.
For me, since I want these kinds of long-term projects, it represents a good value!