Aside from the build your own, I would really like to have some of my lasers tested with a spectrometer so I know exactly what wavelengths they are. I live in New Mexico and I’m not sure who could do it. Any suggestions?
There are a few members here who own spectrometers, most of them will probably measure your laser for the cost of shipping.
I'm sure some of them may see this thread and offer their services.
If you're able to measure and set up a diffraction grating in a decently precise way indoors (or measure long enough distances and have a large flat wall & a friend to help outside), you could measure your lasers yourself with a cheap diffraction grating ordered online.
Apply a bit of trigonometry and all you need is a grating of known line-spacing and a way of accurately measuring distance.
I'm going to do this at some point as there is a large flat field with a wide building nearby where I live, so I'll borrow a long tape measure (or even better a laser tape measure ) and set up outside for it.