What are the benefits of getting a prescription?

[Hairwatcher]

I've read on a few sites about the need to talk to your doctor and to get a prescription before going down the finasteride route. Apart from the medical advice is there any financial benefit to doing this if you're in the UK. Propecia/finasteride doesn't seem to be available on the NHS so you're still left having to buy the stuff anyway. And the prices in chemists in the UK seem to be way more expensive than those for the generics offered in online pharmacies. So why get a prescription?

Also, has anyone here from the UK ever gotten a prescription for Proscar but for hairloss?