Connie, you're probably looking into what is call HT in a box or All in one HT (home theater) where there a DVD player with built-in amplifier inside or a built-in amp to the sub where it all connected.
Speakers need amplifier unless it's one of those Harman Kardon where you only plug-in to your phone jack but not very powerful. If the unit need to be plugged into a power outlet then it has amplifier.
What you probably want is powered or amplified speakers, where the amplifier is built into the speakers; like the computer speakers.