What are you planning to 'test' for? Everything listed in these replies is pretty much spot on.
I would like to point out that one of the things that makes the 'full size' dynamic cardioid mics like SM58's appropriate for vocals is the ability to handhold them, move them, drag the cord around etc., and not get a bunch of 'racket' as a result. I've dropped 'em many times on stage as a lead vocalist over the years and the do take beating very well. I never killed a 58 yet! The 58 has a nice little bump in the mid-range that adds nice presence. It seems to roll way off above 12k no matter where it's placed, and down in the lowest octaves unless they are right on top of the source. Watch a good audio/video of a performer with an SM58 and you can see them moving the mic in close and out farther away in tailoring their sound to their personal range and it's strengths, or to create the vocal presence and intimacy they may be looking for. You can pick 'em up reasonably priced or even used and find a ready market for them if you find that they are not what you wanted.
The SM57 is very similar from a 'noise' perspective. It lacks quite the same bump in the mid-range as the 58 has, is a bit better in the very bottom, but not really a great kick drum mic, but can be a decent electric bass amp mic. Used often for horns, amplified guitar, etc.
I can't over state that these are not really recording mics. They are stage performance mics. "Dropped, beer spattered, smoke blown thru them, harmonicas banging into 'em, point 'em at the monitor almost and still don't have feedback, dropped again, thrown into into a suitcase on top of the cords until the next night" and worth every penny!
Go to the studio and nobody every asked me if I 'would like to be using an SM58 or SM57'? In that world the vocalist didn't touch the mans microphones. At all (and he picked 'em)! 'Stand back' ,'watch your sibilance', 'back off even more if you're going to roar like that!' That world had an ancient RCA ribbon mic worth thousands, or maybe a more modern AKG equivalent (still very pricey and usually they only owned one) in them and if you popped a 'P' too loud the engineer reminded you the next one was going onto the studio tab at a couple hundred bucks while he had the mic sent out and the studio used nothing till the ribbon was replaced.
So it comes back to, what are you testing for, what kind of singing, solo, duets, harmonies, what is the vocalists range, style, what dynamics can you expect from the vocalists performance, how much of the 'room' do you want to hear or ignore. There are moderately priced attempts at large diameter condensers with all kinds of patterns (including adjustable) that need phantom power out there but I don't think $200 is gonna show you what a truly great vocal studio mic can be. Borrow what you can from whomever you can, or get an SM58 to start with so you can at least get some of your money back if it's not what you wanted. Plus you'll learn about one of the most common microphones in the music industry. Reply when you've tried one or more, tell us some more, and somebody out here has some good advice for free.