Head unit

[Nadhunt]

Hi
I’ve got a 09 plate with a basic cd head unit.
Does have a Bluetooth function in menu but doesn’t seem to do anything.
Would like to put in a unit with Bluetooth and dab.
Is this a diy job?
Best to get a oem off eBay? Is so which one
Or a new unit? Spend under £100 if possible but up to 250

Thanks
Dan