Materials required tends to be limited to one or two pop bottles, some putty or Blu-Tack, a bicycle pump and an adaptor and making use of a sharp knife.
Parachutes can be as simple as a bin-liner and still work well despite their low cost.
In short, if you can use a bicycle pump, use a knife without cutting yourself and use a browser, you should be able to launch a water rocket. I have now got around to building a launcher of my own and you can also look at this design - feel free to build one of your own and don't hesitate to let me know of any tips or problems. Before you build or launch anything, read through all of the water rocket pages on this site as they contain tips that are not repeated everywhere. A list of home links is on the Site Map - just click on the map icon in the lower left on any page to see the site map. Even though that with an ordinary bicycle pump, you can never get as high a pressure as you can get in a supermarket pop bottle, you should still Play Safe .