password protection/encryption

Greetings, I'm working on a project that involves a password protected area of a website. Some one also involved brought up the point that this area should be secure (Whit the lock icon indicating it is encrypted). In this particular project the password protected area will be a quote generating system for a company. Users would log in and choose the products they are interested in purchasing and the site would generate a quote depending on what they selected from the list of products. So my question is.. At what point is encryption necessary? I've always thought encryption was only needed when dealing with stuff like credit card information, am I wrong? How secure is a password protected page done with just PHP? Thanks Chris