In the long run, yes, rainwater harvesting is worth the investment. Even though store-bought rain barrels can cost up to $200, you can build a less expensive DIY rain barrel out of a trash can, plastic drum, or pretty much any large plastic container that can hold water.  However much you spend on your rain barrel, you can expect it to pay you back in free water over the years. At the same time, you're contributing to global water conservation efforts, which is priceless.