I am not sure which zen you are talking about. But my brother has a zen stone plus 2GB (with small round blue screen) and the radio reception is very very bad. This is mentioned in reviews on internet also about the reception. So please keep this in mind and if you get a chance listen to the player (esp radio) if someone has it and then decide. Although you may have main requirement as MP3 only but if you have a radio it should work regardless of you using it or not.
You can opt for others like sansa clip and i suppose they have lately introduced the sansa clip+ which boasts of FLAC support and is supposed to be inexpensive.