Uh... You must not know much about the history of browsers. Practically every browser designed for consumer operating systems cost money back then. Netscape Navigator was made free, but only for individuals, academics and researchers. Many individuals still paid for the full Netscape Communicator suite though. Netscape's IPO was probably the most successful tech IPO ever at the time, and their revenue increased significantly quarter over quarter. People would go to shops and buy boxed copies of Netscape.

That was the case until Microsoft bundled IE with Windows. That was one of the major points of the Microsoft antitrust lawsuit - browser developers were losing a lot of money because Microsoft were abusing their dominance and bundling IE for free.

Netscape became fully free in 1998 since there was not other way they'd be able to compete with IE. The code was open-sourced and became what we know as Firefox today.