Getting good sound is not all about spending money.
Ever listen to an old radio show from the early 30's or 40's? Wow! Sounds really good.
The reason it sounds so good is because they used the basics - keep the mic close to the mouth for the best sound.
Although this video shows a cheap Stony Edge desktop mic, it also shows that as long as you keep the mic close to your mouth, and set the levels properly so it's not over peaking or under peaking, chances are it will sound pretty good.
And that pretty much goes for any mic, expensive or not.
The Basic Filmmaker