You could just sell a copy, but hey I guess I'm old fashioned thinking selling a product in exchange for money is better than selling eyeballs to advertisers.
Out of curiosity, has anyone tried that strategy with any success post-Opera? They're the last I remember to sell significant numbers of copies of a browser. Depending on how you count, that ended in either 2000 (when they introduced a free ad-supported version, though you could still pay for a registered, ad-free version), or 2005 (when the paid version was phased out entirely).
It's pretty hard to that and keep the project open-source. If you don't keep it open-source, the amount of bugs to fix will overwhelm you and it will be just a failure.
