There are many mice and some touchpads available that provides you a middle mouse button. In general mouse and touch pads doesn’t provides you the third click button i.e. middle click but now problem you can use third click by pressing both mouse buttons at the same time. This is more easy on laptops becuase there you have to put your finger on the place where both (left & right) click buttons meet each other (in center) and press both of them together, it seems difficult but its very easy. Or on a mouse with a a scroll wheel, you can usually press directly down on the scroll wheel to middle-click.