The biggest benefits in usability are easy to implement, including:

• Removing unnecessary, unimportant, distracting stuff and tactics from your website.
• Going 'left' instead of 'right' (or vice versa.)
• Rewriting, rewording, editing.
• Adding text and links.

Often the more money you spent on the graphic design of a site, the less usable it will be! By focusing on usability you can avoid unnecessary expenses that will ultimately chase your users away.

At the same time, usability is emotionally hard...