Buying stock is not the same as buying a new retail product. When you buy stock, you are buying shares previously owned. Stock is not a consumer item.
So you are off here. You will no longer pay 15% capital gain on investment income because capital gain tax is repealed and eliminated under the FairTax.
You will pay a consumption tax only when you consume.
My house is owned by a C Corp. So if I sold it I could just sell the stock instead. Any big transactions would just be a stock sale. Hmm I guess my house is previously owned too so it wouldn't be taxed even if I just sold it outright. I just don't see where the tax revenues come from then : (