Si-glass microfluidics have long provided unprecedented precision, robustness and optical clarity. However, chip fabrication is costly (∼500 USD per chip) and in practice, devices are not heavily reused. We present a method to reduce the cost-per-chip by two orders of magnitude (∼5 USD per chip), rendering Si-glass microfluidics disposable for many applications. The strategy is based on reducing the area of the chip and a whole-chip manifolding strategy that achieves reliable high-pressure high-temperature fluid connectivity. The resulting system was validated at 130 bar and 95 °C and demonstrated in both energy and carbon capture applications. We studied heavy oil flooding with brine, polymer, and surfactant polymer solutions and found the surfactant polymer as the most effective solution which recovered ∼80% of the oil with the least amount of injection while maintaining a relatively uniform displacement front. In a carbon capture application, we measured the dilation of an emerging ionic liquid analog, choline chloride with urea, in gaseous and supercritical CO2. Previously restricted to niche microfluidic applications, the approach here brings the established benefits of Si-glass microfluidics to a broad range of applications.