There is also Opera from Opera Software. Version 4.0 of the decidedly different browser is now available for download. The answer may be yes. In the past, minor upgrades have been free while major upgrades have been half the price. A much more significant difference between Opera and either IE or Navigator is market share.
Opera has virtually none.
But then, neither does any other browser besides the big two. However, not only does Opera offer some unusual and useful features, but the browser's core could show up in Internet appliances. One of those features allows end users to take back some control over the browsing experience. Power users can configure the browser to their liking. With version 4.0, cookies can be displayed and filtered.