(web site in german, but you’ll be able to find out how to do it)
German magazine PC Welt has a free version of WinRAR 3.80, yours for the taking.
Go to the web site, fill in first name, last name, and your email (twice), and they’ll send you a link to download a key.
Valid until March 15th 2010. They will also offer a discounted update to version 3.91.