Tools needed: hacksaw, rubber mallet, and drill. Materials needed: PVC pipes, elbows, t joints, and valves.
My system: I also have rain barrels that collect water from the roof gutters- those barrels are used to water the attached green house (instructable to come). The rain barrels that you see here are in my garden and are filled by a basement sump pump. You would be AMAZED at just how much ground water one house pumps out in one day. I am in Central Illinois and I have been getting between 35-50 gallons/day. Each rain barrel holds 55 gallons! 3 barrels= 165 gallons.
Planning your system: How many rainbarrels you will need will depend on how long your total drip line length is and what the total area of your hole size is.. My garden is roughly about 400 sq feet and I had about 110 feet of drip line with pin sized holes every 1 foot. You can accurately figure out how much water weight you need using the bernoulli's fluid principles http://en.wikipedia.org/wiki/Bernoulli%27s_principle
Construction: PVC pipe is very easy to work with...think big-boy legos! you can cut the pipe with a hack saw and drill drip line with the smallest diameter drill bit you have. There is no need for plumbing glue. This is a drip system so by definition the pipes are supposed to leak! The pressure isn't great enough anyway to leak around connections.
3d printed connections: You can use the attached max file to print out a connection that can be glued to the bottom of 2-liter soda bottles. When glue dries, screw together and repeat! Soon you will have your own rainbarrels that can be used in your new drip system design!