If you want to keep it simple, take a look at the Koss MS459 cassette player. This inexpensive in-dash unit has 15 x 4 watts of power, a pre-out jack and an auxiliary input for adding on additional car audio equipment. You can adjust the sound to your liking with the bass, treble, balance and fader controls and you'll have plenty of musical variety to choose from with 30 radio station presets.
1 Not bad for $40
This is a great little deck for the price you pay. Sounds good. It would be a great upgrade from a deck w/o a cassette player or a broken cassette player.