DJ mixers and their functionality are different to stage or live mixing desks. There are many misconceptions about what a DJ mixer is and how it is used. They have more features, such as trackers, filters, beat slicing and effects that a live mixer can't offer. You can also buy a basic DJ Mixer without all the features; hence at a much lower price. Get to know the features of a DJ mixer and decide which one meets your needs.
Of course, DJ Mixers are smaller in comparison to stage mixers, whioh have more channels because they need them. For example if you are live on stage, there is often more than one instrument, or a group of singers that would need more mixer inputs. DJ mixers can sometimes only have 2 stereo channels and have a crossfader which allows you to mix different songs together. Plus, they are more compact and easier to transport.