It depends on what you want this spectrometer to do. Public Lab spectrometer is interesting and cheap, but the performance is very very limited. If you need so

It depends on what you want this spectrometer to do. Public Lab spectrometer is interesting and cheap, but the performance is very very limited. If you need something better you can search eBay for used (scanning) monochromators. Next step is to check Ocean Optics or Hamamatsu catalogs: they have good line of products, but those are in 1000 USD+ range.