You're being ripped off. Mine is free. Of course I have to get the nurse to inject it, I'd rather pay the £8.20 to do it myself. Although I'm a little bit in love with one of the 2 nurses I normally see.
You only get free prescriptions if you have an NHS exemption card?
Unless your medication is going to your doctors surgery directly... they might catch up with you one day. Be careful there!