The Halfords discount voucher available via the members section in this forum explicitly excludes “technology products”.
What is the spec of your car? I ask as my 2009 Sport Tech has BOSE and bluetooth (for phone calls) built in and I use a £13 bluetooth receiver (with a £5 low profile cigarette to USB adapter) which connects via the AUX and works for playing music and internet streaming from the same phone.
I get by with FM from the built-in BOSE unit and have never loaded a CD.
I guess it comes back to what you require and how sexy (and therefore expensive) you want it to be?