The sale of personal goods is not considered revenue. Since these types of sales are taxed at the provincial level and you don't need to remit taxes on the sale nobody really cares if I sell a used guitar to the guy next door, especially CRA. It is only the sales of property that becomes a capital gain of which one would have to declare as revenue.It doesn't matter if its profit or loss.. he's selling guitars. This is NOT the same as the stock market or other regulated assets. The CRA sees it as income which is taxed in Canada.