I've been wanting rain barrels almost as long as we've owned our house - it'll be 3 years in August. When I first priced them online I was shocked that some people wanted $100 or more for one - and I have eight downspouts, including the garage! Then I found out you can make your own - all you need is a 55-gallon food-grade barrel.
The hardest part for me was locating a local source for these things. A friend who gives rain barrel workshops at the Sustainability Institute gave me the name of a local supplier who sells them for $40. We're not exactly rich here, so the price kept me away for a little while longer. Finally, I started a garden fund and had accumulated a little cash - my wife saw an ad in the paper selling food-grade barrels for $20. I jumped at the opportunity and bought two of them - mine must have contained lemon juice! That was in early February - the barrels sat in the yard for at least a month until I made time for them. - did I mention I'm landscaping and vegetable gardening?
There are many different ways to create these rain barrels, but they are all very similar. Over the last few months I've been watching "how to make a rain barrel" videos on the internet, trying to get an idea of the way I wanted to make mine. In general, I decided I like the Paul James video the best. I diagrammed the parts I would need and when I got to Lowe's I discovered that the specific parts that were used in the video were not necessarily the most common parts in their inventory. So I had to improvise again. I find that any makeshift plumbing project I undertake always includes improvisation when I get to Lowes!
Once I got home, I found I needed additional tools and the drill needed to be charged. I finished over a couple of days and also had a lot of site preparation to do. I had to cut the downspout to fit the barrel and I put down landscape fabric to prevent weeds from growing around it - the less I have to use the weedeater the better. I had to make sure the ground was level so it won't tip over when it's full. All of that is done - I just have to finish landscaping around it and hope I did everything right. Now on to the next one.
PS - improvising as I did, I think it took me longer than it would have, but the next one should go a lot smoother, now that I have all the tools and have done this once already.