The Neumann U87 condenser microphone is the absolute standard for recording perfect vocals. You will be amazed at the difference in sound quailty that comes from recording vocals with an extremely high quality mic like this.
You will be able to find a Neumann U87 microphones for sale online both new & used. You shouldn't be afraid to buy a used microphone of this type because they are well known for being extremely durable. If the mic seems to be in good shape then it probably works fine (like new.)
CLICK HERE TO BUY THE NEUMANN U87
for other (cheaper) condenser microphones - click here.