Yes pretty much all DVD players will play back CDs though the TV's audio system. It's your call if that counts or not, my Sony player even does a "Visulation thing" when it plays back audio only. The TVs don't have the "best" audio system. There are some EARLY DVD players which won't, but I can't say I've seen one for sale in the last 10 years or so.
Most newer DVD players will play MP3, and Windows Media, some even play Ogg in addition to the CD Audio.
I bought one that is the size of of a small purse (approx. 3 x 8?) at the apple store for $99 and have used it for numerous trips and I use it at home in the kitchen. We don't have wireless speakers.