Instant dolly, no equipment, just simple duct tape, and the side panel of a PC.
What do you see? A levitating piece of aluminium? Almost there!

Dot made this video with this video dolly.

Step 1: Get a Flat Rigid Plane, Here an Aluminium PC Side Panel (structured)

First of all, it is not my invention, it is just a quick way my friend Dot http://www.dotmancando.net made.
With super limited budget and time, we needed something to make a video dolly, so a plane surface with perhaps wheels (soft ones) for a smooth linear movement. The aluminium side panel of a PC was the nearest flat element at that moment... (not with the wheels of course).

Step 2: Tapping the Wheels

Than it is placing the duct tape
- on the flat surface as if it were a double-sided tape (roll it).
- don't put the lateral support tape before you stick the wheel, stick the lateral support tape after the wheel is stuck to the plane, this is just to show you the relative position of the pieces of tapes.

The PC side was very good : the aluminium profile provided us a useful guide for parallel positioning of the wheels.

Dot got the wheels and duct tape from http://www.diy.com, total less than ÃÂ£10 and 5 minutes to build. I recommend you get soft wheels, the softer the less noise (contact with video camera).