I lighten the background with a highlighting tool on picmonkey.com. It's meant to add highlights to hair, but who follows those rules anyway? :P
I like it because it'll not only lighten the background, but I can control if i'd like to lighten the item as well. Overall, it works out really well with my listing photos. I don't know what I'd do without it, especially since I'm incapable of taking a photo that looks good without being edited.