On the other hand, buying something inexpensive from a garden center to practice on with the understanding that it will never be great can be a good strategy when you are stating off. This can be especially true if you don't have a green thumb for potted plants, don't live near an actual bonsai nursery, are unsure what to look for in good-great starter material, are unsure how much you will love this new hobby or your budget is a little tight.
This is what I did and 4 years later I am ready to start spending significantly more money on unrefined stock. I just need to make some space on my benches for new friends.