Breadboard is a cool idea, but your first experiments will likely be super simple right?
Here’s a few thoughts.
How about some double conducting copper tape and sheets of craft paper or cardboard. (Double conducting conducts on the top as well as the sticky side so overlapping joins completes the circuit).
You can draw/plan and then route the copper sticky tape like a circuit board. Fashion basic switches from the copper tape around a cardboard flap, tape down any “flat” components like resistors.
Add some tinned leads to anything that would stick up from the board.
I often find the more tactile “MacGyver” approach is a better teaching aid as there’s no mystery behind the scenes (no hidden board wires, no pre-mounted components or connectors). Everything is built up from existing skills and experiences.
When you start to get more advanced, 80s Aussie kids grew up with:
That has a complete list of components needed for the projects in the book. Same idea as the copper tape, just with bits of wire and screws. The project in the book were all built onto a pre-drilled block of plastic with the schematic laid on top. They were fun little projects and easy enough to do - the flashers and sirens were a hit for me.