Since going public in late 1985, Costco Wholesale (COST -0.36%) stock is up nearly 80,000% and that's before factoring in dividends. To make this percentage more tangible, if an investor put $10,000 to work in Costco stock in 1985, they'd have nearly$8 million today. Even if investors had waited until five years ago to buy Costco stock, they'd still be up more than 200%. That's more than double the return of the S&P 500 during this time. Costco stock has been a life-changing investment for many people but ...