There are sometimes proposals to introduce a small fee to see a GP (General Practitioner - the first line family doctor that you'd go to see for anything not an emergency who'd refer you to other doctors for serious stuff that needs hospital treatment or prescribe meds otherwise).
GPs do get a lot of people who don't really need to be there, and it'd be nice if those people would use telephone triage systems like NHS Direct, or go and see a pharmacist. Having said that, an alarming number of people die from preventable illnesses because they "don't want to bother a doctor", so it does work both ways.
While England does have prescription charges only about 80% of people on prescription meds pay that charge, because there's a wide range of exemptions.
There has been research showing that a lot of people don't comply with medication. Interestingly the severity of the illness doesn't make much difference, and neither does having to pay or not pay for the meds. A surprising number of organ transplants fail because people don't comply with the regime of medication. This occurs in the UK (free meds and free surgery) and in the US (expensive meds, expensive surgery). It's made clear to the patients what the result of not taking the meds will be, and the patients know they're lucky to get an organ, and etc etc.
tl;dr I agree that most people don't abuse the UK health system. And the cost isn't something that enables people to abuse it or not.