Hi Oma,
All the browsers are free these days, if you download them. You can download IE 7 at:
http://www.microsoft.com/windows/ie/default.mspx
or, you can order a CD from that site, for $9.50, if you don't want to download it, (it takes a long time to download on a dial-up connection).
You can download the latest version of Firefox at:
http://www.mozilla.org/download.html
Note that Firefox is only a browser, (it does not include an email client), Thunderbird is Mozilla's stand-alone email client. SeaMonkey is a suite that includes both a browser and an email client. Most people who use Mozilla products, use Firefox and Thunderbird, rather than SeaMonkey. On a dial-up connection, especially, Firefox downloads much faster than IE, and it also performs noticeably faster, when you're using it.
An added advantage for Firefox and Thunderbird, is that most viruses and security issues seem to be directed at Microsoft products. IE is an excellent browser, though, it's just not as fast as some of the other browsers.
Love,
Tex