I think the concern about junking one's car is a common one. I've have it every time I've gone on track.
And BigPete did unfortunately total his beautiful '8 at Snetterton. So it seems to me that it is a very real and valid concern.
However, I think the risk is generally pretty low except on places like the Nurburgring where there are no run-off areas and the track is surrounded by Armco or concrete just a couple of feet off the track.
'Normal' circuits usually have good run-off areas where people are most likely to run-off. So provided you don't go too hard or you're not a bit unlucky (as can happen), you'll normally be OK. Blyton is virtually all run-off area, and it's a great circuit to build confidence, IMHO.
As to tyre and pad wear, again it just depends on how hard you go. Under Steve Lewis's coaching at Blyton last year, I chomped through a set of brand new Racing Brake ET500 pads in just over half a day. But, that was with Steve encouraging me to absolutely go for it, and him saying at the end of the day 'well, you're getting all you can from the car now'. So that's pushing it about as hard as you can in an '8, e.g. hard on the throttle up to any sharpish corner and hit the brakes seriously late until the ABS starts to bite (as a rough rule of thumb). That will eat pads.
Drive just a bit more sensibly and you won't see anything like that amount of wear to either pads or tyres.
Personally, I would also recommend tuition; either from a club member with lots of experience, or a professional driver such as Steve. They can teach you heaps (even if it takes a while to learn ..

) and keep you and your car in one piece whilst you learn. A nice side-effect of the tuition is that it will make your track insurance cheaper, too.
The only other thing to bear in mind, is that there really isn't any pressure (other than any you may load on yourself) to go fast. If other people are going faster than you, just let them overtake. Who cares? Unless you allow it to happen or make it one it isn't a competition, a race or a willy-waving exercise. (And on track days the first two are explicitly forbidden, though the third is harder to legislate for) At any point in time on the track you normally will have some people going fast, some possibly as fast as they can, whilst some others may be doing exploratory laps or trying to concentrate on their lines and going quite slowly. Just use you mirrors and at places like Blyton you should have no issues at all.
