JAWS is insanely, incredibly expensive. If you're on Windows,
$1 is a completely free option, and in my opinion, it's even much better than JAWS. NVDA is open source, and developed entirely by blind programmers. For a web browser, Firefox is you're best bet, and Thunderbird is the most accessible option for email.
If you're on mac, of course, you get a screen-reader built in for free. And the built-in mail app and web browser are perfectly accessible, and your best option on mac.