Mutual funds have been around for decades, but it’s been just the last 25 years or so that their popularity has skyrocketed, due in large part to the growing participation in 401(k) retirement plans, which made mutual funds household names. About a decade ago, exchange-traded funds (ETFs) gained traction with individual investors and began to give mutual funds some heavy competition. And in the past few years, they have also emerged as good vehicles in which to park retirement money. But what many investors don’t realize is that there is another vehicle (besides mutual funds), which also offers you a means to pool your money with others to buy shares, at nominal costs.