A simple tool for a white background?

Hi everyone,

I'm looking for an easy way to make the background of my photos white, but I really don't want to hassle with Photoshop. Every time I try to cut out a subject, I end up spending hours trying to get clean edges and it never looks right in the end.

Do you know any tools (online or free) that let you do it quickly and easily? I just want a clean result without having to become a photo-editing pro.