To play DVDs, you have to have a DVD reader. Look at the drive to see if the dvd symbol is present. It could be a read-only, or read-write. Older pcs might not have a DVD drive. If the cash is significant, buy the DVD, go to your library and transfer .mp3s to your own CDs or memory stick.

Oh, I didn't mean the drive on my computer, which does indeed play DVDs -- I meant the CD player/radio in the kitchen. But your suggestion is still good.

The mp3 format determines what type of SOFTWARE is required to play the FILE.
The DVD or CD format determines what type of HARDWARE is required to play the media (disk) that the files are stored on.
As theora55 says, you cannot play a DVD disk on a CD player. But if you are playing the files on your computer, your computer's optical disk drive may well play both - look at the disk drive cover to see what it is labeled as.
You can always read the files to your hard drive and then burn them to CDs yourself, if the price difference is very high.

All right, I think I got it now, thanks very much.

Many cd music players don't play .mp3s, and probably won't play from a DVD, but if they're .mp3s, they're so portable.

Actually, that is a point. I was assuming that the CD player/radio was an mp3 CD player. But if it does not say so, it will not play mp3 files - only non-mp3 audio CDs.