The feeds are provided by volunteer scanner enthusiasts who use their own personal radios, computers, electricity, and networks at their own cost.
A feed's "quality" could be affected by many things, such as the quality of the signals on the system itself, simulcast issues, location, scanner, antenna, etc. Sometimes it takes a little time for the feed provider to fine tune the equipment.
You are permitted to listen-in free of charge. You can also purchase your own scanner.