those waterhogs look amazing, but damn! I have 5 barrels set up around my house in DFW and I'm into it under $100. I had a side shed, so I put 3 up on blocks, plumbed in parallel. Basically the hose connectors drilled into the bottom and regular garden hose cut to feed them. sealed with silicone. Mounting those are a pain in the ass because you have to climb face first into the barrel.
they get fed by flex pipe from the gutter, then through a screen into the first barrel to clean debris. another hose works as an overflow in the first barrel. The barrels are open at the top but screened in. This helps with pressure and keeps mosquitos out.
The other 2 are 1 each at the corners of the house. we got one fancy one that collects from a leaky spot in the gutters I can't reach to fix. that's in front and it's all painted and fancy, looks good. The other is in the back yard and just fills from flex gutter. All of these have spigots at the bottom to fill watering cans.
We mostly use them to drip irrigate the foundation of the house in the summer. IDK why that's a thing, but you have to do it here. Wife also fills watering pots right out of it.
I have a water cooler in the house we drink out of (like from an office). clean water is 35 cents a gallon. So I have maybe 7 of those, always have 2 full and hidden for back ups. rotate the others through.
So in a pinch I have 10-35 gallons of clean, drinkable water before resorting to the barrels. afterwards I have 250+ gallons I can clean or boil and drink. it's nice to water stuff with no water bill.
They fill up stupid fast. I was going to figure out a way to collect off 100% of the roof, as I have maybe 25% covered. But we got a light drizzle for a few hours and they will full the the brim. I like that they automatically cycle clean water through if I don't even drink it, too.