The above rig cost me all of ten cents to make. 

To make something like this is very easy. The first step is to go into your local hardware store and find their lumber section. Most big stores around here carry a wide range of trim, and the stuff you're looking for is the semi-circle trim. I bought a twenty-foot piece of it for $3.50 at Home Depot, and then asked the salesperson to cut it into 4" pieces for me (look ma - no tools required!). If you don't have any copper wiring, I'd suggest picking up a small bit of it while you're at the hardware store as well. 

Now that you have the necessary parts, it's a simple task to put the thing together. Miniatures that have attached bases are a bit harder to work with, and they're covered in the next paragraph. For miniatures with slot bases, simply line up two 4" pieces of wood and put the slot of the miniature in the middle. Press real hard, and tape the two halves together right at the top where the miniature is. You can also tape around other parts of the stick to make it grip the miniature a bit better. See the picture below for an illustration of this method.

Miniatures without that convenient slot are a little bit harder to set up, but with a bit of copper wire, anything is possible. As per the diagram below, wrap a bit of wire around the base of the mini and twist it up under the base so it is nice and tight. Do this twice, to form two pieces of copper hanging down. Then use this hanging bit of copper to secure the mini between the two pieces of wood. Tape it real tight, and that thing won't budge while you are painting.

Now you have a convenient handle on your mini! 

If you are really ambitious, you can also take a block of wood and drill holes in it to match the diameter of the mini handle. This way, you can stick all your current works-in-progress off together and in a place where nothing can rub up against them while you slave away bringing them to life. Plus, to the uninitiated, it looks like some bizarre voodoo shrine of little people. J

The biggest benefit to having this type of handle is obviously for when you are painting your miniature, but an added bonus is that this makes priming your mini a breeze. You can spray the entire mini in one shot and get every nook and cranny, without having to touch a still-wet mini, or wait for one side to dry. There are fancier ways to make a rig like this, but considering the total $5 price tag for 20 plus rigs, this is a simple and cheap way to make your life easier.