Trash cans, plastic ones, that is, make great rain barrels. Our rain collection system for 10 years was plastic trash cans that the drainpipes from the guttering fed into. Dip and carry, but it kept a beautiful garden, beautiful!
If you have your barrel in the summertime, you need to prevent mosquitoes. The easiest way is to put a bacillus thuringensis (pardon the spelling) doughnut in the barrel. BT prevents eggs from hatching. Usually 1/4 doughnut is sufficient for about two months.

You may need to find a way to childproof it. Some kind of latching/locking lid might work. You do not want a child drowning in your rain barrels.

You can use an overflow valve or tube that would then flow over into another trash can, so that you can still have the effect of having some of these larger barrels.

I am currently using my unused landscape in-ground pond. The conditions in my area are such that it is considered a useless yard decoration with the water restrictions, so now when I am home and it is raining, I let it fill up from the rain, but I also use smaller buckets to catch rain and then dispense it in that pond.

I make sure to use the water up in a few days so that it does not contribute as much to any mosquito problems in the general area. For example, even though we did get rain, but there are some plants under the eaves of the house that may not have gotten much of the rain, I then immediately water those with the new rain that was collected.

I also use the water in some spots that are exposed and get rain but they don't get a regular watering from me because my hose can't reach it. So for those areas, I then use the rain water to take care of them in the next few days.