I bought a little garden on aliexpress from the guy who makes it. It's very plug and play and it does about 350-1100nm, which is pretty impressive. I used it to verify how my own DIY sun reproduction setup works. https://www.aliexpress.us/item/3256807055520087.html

There is also this commercial one that is Bluetooth and more portable for around $150, similar spectrum range but lower spectrum resolution than the little garden one. https://www.youtube.com/watch?v=MOXryggwr_Q

https://www.amazon.com/Analytical-Wavelength-340-1000nm-Spec...

The hopocolor vis light ones are also fairly widespread and are more stand alone for about $280: https://www.aliexpress.us/item/3256807972511960.html

My current issue is finding a 250-400nm UV spectrometer or IR spectrometers beyond 1000nm that don't go into the $1000+ range. Standard mass market CMOS sensors don't go into those ranges, so they become far more specialized parts and thus way more pricy.

Mid level, $750: https://www.aseq-instruments.com/LR1.html

Entry (?) untested, $350: https://thunderoptics.fr/product/sma-e-spectrometer/