Well, chances are you are going to have to buy something, but if you want it to be cheaper than Doug's board, you could go to your local electrical supplier or Home Depot or Lowes and pick up some low voltage dimmers. They do exist, I know that Lutron makes some. Then pick up or cannibalize some 10v DC transformer bricks (from things like a DiscMan) and wire it up through the
dimmer to your strobe.
Make sure you read the manual on your fixture so that you get the polarity right or it will never work again. I don't know anything about the strobe you have, but it isn't hard to make the 0-10v dimmer.
If you read through our forums though, you will find that we try to advocate doing things the right way as opposed to klooging things together. When you take shortcuts and do it yourself you run a great risk of damaging your equipment and possibly yourself, especially if you don't know how to do what you want to do. With relatively expensive and useful gear like strobes, it is better to get the part you need from the manufacturer, or from someone who makes what you need. It just makes it less likely that things will go wrong. Plus if you spend the money on good piece of equipment, it will last much longer than something you make yourself.