Plastic CD Holders               

I have blown this picture up a bit so it is not that clear, but if you look on the top of the far 'leg' you can see that the grey plastic cap has been removed to show a nut. This shows how the thing is made. It is made in modules. All the green 'horseshoe' shapes are the same and they will have been injection moulded, they have three holes in and they drop onto the three 'legs' on the left right and middle. Once on the nut is screwed on to secure them (screw threading here). The longer the legs the higher the tower. The grey base which is less complicated than the green bits could have been vacuum formed. Type of plastic ACRYLIC or ABS (animation here )

Injection moulding shown here

Vacuum forming here

This is another one that is made in modules, in other words as you CD selection grows you can add another module and then another and so on. All of this one is injection moulded I think (follow the link above). Type of plastic probably ABS other plastic types here
Yep you got it, it's made of units again. The upright pieces are all the same (except the colour) and they are held together by small 'bars' also all the same, which keep the unit stable. The brightly coloured one would be more for a young persons room, the grey one more for a lounge. I think it looks like you could keep adding units either next to the ones shown or above them to make them taller. You could even lay it down and put the CD's in from above. Its very versatile this one. How are the parts made, complicated shapes - I'm afraid so - injection moulding (the link is on the first picture above).
The plastic sides have little holes in them, I think these are for fixing the next unit to this one. The sides are injected (see link above). The plastic tubes are to space the sides exactly so the or game fits in. I think the plastic tubes are made by a process called extrusion moulding, take a look here . The type of plastic, probably acrylic. Look on the links above for plastic types and animation.