What sort of soil should I use for bonsai?

Most beginners use a general potting mix for bonsai soil until they get the hang of things - and I recommend that you do this too - just until you familiarise yourself with the other processes involved in bonsai. As long as the mix is open and well-draining you should not have a problem and it wont impact negatively on the plant. If you can get pre-made bonsai soil instead however, use it. Bonsai soil is much more free draining than potting soil and doesn't contain as much fertilizer as normal potting soil which is usually for plants in large pots that people want to grow really big. It is usually available at specialist bonsai nurseries, and even some normal nurseries stock it. This is probably the easiest, cheapest and least time consuming way.

Making your own soil mix isn't as hard as you think. A lot of bonsai growers make a bit of an unnecessary fuss about it. A basic bonsai soil mix to use - and one that would apply to almost all species is: one part loam, two parts sphagnum peat moss, two parts granite grit. All of these ingredients should be easy enough to obtain.