I will only buy a single nowadays if there are enough tracks to justify the price. For example, singles with just the original song, the instrumental and one remix aren't going to get me to buy it (unless I really, really love the song in the first place). B-sides and unreleased tracks (sometimes interviews, etc) are a good reason to buy a single. If a single comes with DVD and is reasonably priced, it's another reason why I'd buy it.