There are no cost differences, except that you can pay to get rid of advertising that appears in Opera. They're otherwise all free of purchase cost.
To comprehend this, consider that lots of things are free in this life that other people have labored on: jazz in the park, birthday parties and walking tracks through the forest. They might cost money to make, but no-one's going to send you a bill. Just enjoy such things, don't waste the opportunity.
On features, that's a very long story, but some basic points are:
- Product maturity: Opera, Netscape and Mozilla are more mature.
- Internal quality: Opera, Netscape and Mozilla are better inside.
- Vendor lock-in: IE is the only browser seeking to be non-standard.
- Security: IE has a track record ten times worse than the rest.
- Features: Opera and Mozilla have many small enhancements.
This was first published in November 2004