It ain't as hard as it seems and there are no strict rules unless you enter a show which I never have. Bonsai is merely a tree in a pot. I have a couple of atlas spruce which I bought at Lowes for a couple of bucks a few years ago and are now pretty nice. I dug a gnarly stump of a lilac bush a few years ago and nursed it into growth and finally put it in a bonsai pot. It looks fantastic. A couple of forsithia stumps were trained in root over rock and are coming along. They produce flowers in the spring. I bought a cypress on the internet last year for a few bucks and it grew fast with constant watering all summer. I hope it makes it through the winter. I don't usually buy seeds and of course there are no such things as bonsai seeds but I learned that a species called dawn redwood is a fast grower and the saplings are expensive. It took about a year of a technique called stratefying to get the seeds to finally pop. At one point my wife found a baggie full of dirt in the crisper part of the refrig and almost threw them away. I have a little pot full of sproutlings in the house and I will be curious to see if they do well outside.