Spend a lot of time practicing on like wood, if the stock is maple, buy a piece of maple and carve your design in it. A piece of maple from the lumberyard is a lot cheaper than a gunstock blank. It will teach you techniques and help with muscle memory. But most importantly it will help you learn how to sharpen your chisels. What a new carver thinks is a sharp chisel, is usually a dull chisel.
I believe in buying the sets, the savings usually save enough to cover the costs of one or more of the chisels/gouges. You may not ever use the extra, but sometimes they can be repurposed by changing the shape of the grind. Over the years, I have eventually used the "extra" chisels, either as is or as a repurposed chisel.