This paper describes a method for rapid prototyping of microfluidic devices in Shrinky Dinks polymers by using a cutting plotter. The new method can produce microchannels with controlled dimensions ranging from 5.8 mm to 330 μm, and fluid tests with a dye solution showed no leakage for channel lengths over 1.5 cm. The total processing time to produce devices with this method is less than 10 minutes, which makes it suitable for rapid prototyping of microfluidic designs prior to full-scale development. Additionally, the instrumentation and materials are relatively low cost and can be implemented outside of a clean room environment, thus enabling the development of microfluidic chips by a wide range of researchers.