Microfluidics technology shows a wide variety of applications in multiple research areas. Up to now, most of the microfluidic devices are fabricated in the cleanroom, using the highly sophisticated instruments. With the desire to make the microfluidic systems more accessible to chemical or biological researchers, a series of low-cost fabrication technologies for polymer-based microfluidic systems will be introduced in this research. With the help of these proposed low-cost and cleanroom-free fabrication methods for polymer-based microfluidic devices, users could easily fabricate their own microfluidic devices based on their usage. These proposed low-cost fabrication technologies covered all three steps of the microfluidic systems fabrication processes, which are microchannel fabrication, microchannel sealing (bonding) and integration technologies. For microchannel fabrication, different low-cost methods such as laser ablation and deep-UV patterning will be introduced in this research. For microchannel sealing method, the thermocompression bonding technology will be investigated in detail. For integration technologies in microfluidic systems, various kinds of low-cost integration technologies for microlenses, metal electrodes and wafer dicing will be introduced. In this research, the introduced low-cost fabrication technologies for microfluidic systems are based on different polymer materials such as poly(methyl methacrylate) (PMMA), polystyrene (PS) and polydimethylsiloxane (PDMS). The fabrication, bonding and integration methods introduced in this research can be widely adapted to different polymer materials. This research offers a flexible choice of polymer materials and fabrication technologies to maximize the utility for researchers, and could be beneficial to lower the access of microfluidics technologies in chemical and biological fields.