For the show, please make sure the sides do not have wire. They should be close-sided to use at the show. It is always a good idea to have a spare cage on hand just in case... just in case one rat is sick and needs a hospital tank, or needs to be fed medications away from the other rats.  Or if you get a new little one who needs quarantining, or even if you're traveling with your rats. 

1.  Go to your local discount department store, like Wal-Mart or Target.

2.  Find a transparent plastic tub, the type with the clip-on lids.

3.  Cut the flat bit of the lid out, leaving a 1/2 inch edge around the sides.  You can do this by drilling four large holes in each corner and inserting a hacksaw to cut it out.  Smooth any sharp edges with a file.

4.  Cut a piece of wire mesh to fit inside the lid so it overlaps the 1/2 inch edges.  You can buy wire mesh for only a few dollars from a hardware store.

5.  Drill two small holes in each corner of the lid and use cable ties or twisted wire to hold the wire mesh in place.

6.  Attach a water bottle.  Drill a hole for the nozzle to poke through and use stick-on velcro to attach the bottle to the outside of the tank, or hang it inside from the wire lid.

7.  Velcro on a flat backed plastic parrot feeder inside the cage so that the food bowl isn't tossed around in transit.

8.  Make it comfy and homey.  You can drill 4 small holes and string up a hammock (or use suction cup hooks), or add a shoebox as a handy nest box and shelf in one.

And there you have it... a simple cheap spare cage.

Note:  These tubs are also good to have on hand if your need to evacuate your home in an emergency, especially if your rat cages are rather large and cumbersome.  Ensure you have enough to house all your rats in same sex groups.  They stack easily so don't take up much room.

Or you can pick one up with a water bottle and small food dish pre-made by CARE.