2003 s60
Radio changes station unpredictably. Is there a fix or do I need a new car?

 

garlic and strategically placed crosses should help. Either that or you can replace the radio head unit (check out eBay etc. ). Not sure if your radio model needs a code - if going used you may need the code or the VIN from the donor car. Alternatively, you can shop for a replacement (check out crutchfield.com to start) and install an aftermarket with modern features like bluetooth etc.