Meh, I have never wasted much time on monitor calibration stuff.
You can spend a lot of money but its hard to hold that fancy monitor next to a fender...I've seen the prices on some color sampler devices but I find even a well taken phone picture provide a pretty good starting point to match a color with a few test swatches and some xp.
Even if you can hold a paint chip next to the monitor...with different finishes on samples/monitor/paint chips and light sources it doesnt help to tell the customer "Well...it matched on my monitor.....*awkward silence*...."
Test prints can be put right up against things to compare, get approval and cover your ass.
You need to know what the rip/profile/printer is doing with your stuff and after a few test prints/jobs you will get to know what your cmyk or rgb to actual output is on various printers you may encounter.
If you want to spend money on a monitor I would get the biggest wacom cintiq you can afford...at least thats pretty good out of the box and investment in your design/ergonomics and not just a color matching time sink.