Ask HN: Do you make physical prototypes? Of What?

I am very visual and prototypes help me design things. For largeish projects I have been having trouble finding material; most recently to model a small building and roof redesign.

I was thinking about how great it would be to have home Depot materials at 1/8 scale but have only found pretty expensive balsa wood at local craft stores.

Is there a Lego type product that is meant to be representative of real world materials?