Buying great businesses when they're on sale is an excellent wealth-building strategy.With volatility returning to the stock market in recent days, patient investors may soon have an opportunity to scoop up shares of some outstanding companies at a discount. Here are three elite stocks to place near the top of your buy list.Costco WholesaleConsumers love to buy quality merchandise at bargain prices. Costco Wholesale (COST -0.77%) has long made masterful use of this simple yet difficult-to-replicate formula ...