I have four 330 gallon rain water containers that are quickly filling up in this rain.
The tanks are about $100 on Craigslist and many vendors will deliver. Be sure you know what was stored in them before. Food grade items only should be used. I keep these on the far side of the house where they aren't seen. I feed the water to them using nicer looking 55 gallon rain barrells connected by hoses. I use the water to fill my pool (it gets chorinated) and to water my landscaping. So 1760 gallons of potential water savings in every one inch rain.
The cost is nominal and the water is free. I can also hook these up to a hose and do drip irrigation or attach a small pump and add pressure for a sprinkler.
It's an easy system to install and great for the environment.