Actually all materials for modelling can be found in a dumpster. Literally.
The very good source for copper/brass wires of different diameters is the old electronic stuff. There is plenty of coils, wires, electrical transformers etc, in these devices. Also small screws, nuts and bolts ....
Plastic ( both the clear and colour one ) can be from housing of the devices, wrappers and many different plastic boxes lying just around us ...
The plywood and wood can be obtained from old furniture. The old picture frames are nice for the wooden or plastic ( if made of ) frame for a diorama base.
Aluminium ( including aluminium foil if needed) can be from many cans for beverages , beer etc ...
Styrofoam ( styropian ) is in boxes of many electronic devices, furniture etc ...
A good quality cardboard ( paper ) can be used from many cardboard boxes used for package of cosmetics, sweets small eletronic devices and even clothes.
I could name more but it is not possible to mention all of them.