This paper shows simulated and measured results of ultra-low cost metal mesh filters in the millimetre-wave and THz bands. It provides a broad overview of the filters currently available and their suitability for ultra-low cost applications. We demonstrate scalable conventional metal mesh filters on standard 525 µm fused silica substrates. In additional, trapped-mode excitation is used to improve out-of-band rejection at higher frequencies. The measured results show that these filters are scalable in the THz range using cost-effective micromachining manufacturing. This potentially opens up the possibility of using metal mesh filters for ultra-low cost applications.