Sure thing!

For the barrels, they were simply sold with the bases. Didn't see a reason not to use them, and also allowed me to drill the hole for the hose connector as close to the bottom as possible (used both for filling water in and for leveling between the two barrels, since the pump is only in one of the barrels, see last picture). I don't remember what the barrels cost exactly, but it wasn't too much and I'm happy with the sturdiness.

For the compost bin, we could have gone a bit more expensive tbh. This one was <25€, and as you can see, it's not exactly shaping up to be a paragon of longevity. It sits on some slabs that were already in that corner, and I though it might help drain excess water...? Not sure though, I don't think it does anything. The compost bin is also too small (and unsturdy) to go in with a shovel from the top and dig the compost over, which would really be beneficial. But still worth it. We put all our kitchen scraps in, almost completely eliminating residual waste bad usage for us, and I pull about 70l of compost out of it each spring.

If you have a place where you can place the bin in the garden rather than on the deck, dot it, I'd say. Take a look around youtube or something, there's some really cool composting systems.

Good luck! Hope the pictures help. Sorry for being so slow to respond.