Got millions of MP3's on the PC at home but my head unit in the car doesn't play MP3's so i need to change it i guess or is there a better way to go?

Its a UK MY00, plenty of mods but still got the standard OE stereo. The one with a tape in it

 

If you have an Ipod, I understand that there's a cassette-shaped gadget that you slot in, and this connects to your ipod so you can play it via the cassette.

My son desperately wants me to buy a cassette player for the car so he can use his ipod I finally shut him up by showing him there are more modern connectors out there.

 

No iPod here, refuse to spend that amount of money on a gadget that will cost £4.20 in a few months time

 

Go ahead and get an MP3 stereo then, there's loads about the £100 mark. Upgrade your speakers while your at it.