Google "freshwater photometer". There are devices for single parameter testing and a $400 unit that tests everything but you still have to buy the reagents and do the drops/mixing. Basically, these do the same as reading the test with your eyes but much more accurately.
You could get a digital probe meter but that's even more $.
The question is, how much accuracy do you NEED? I'm OK with looking at an orange vial and knowing it has some nitrate but not too much (or it would be red) and doing a regularly scheduled water change. My "master" kit was $19 and was only lacking the hardness tests (which aren't terribly expensive either).