Some good points raised so far in the thread.
Agree on the trader reputation, all sites I came from have it. As normal rep should be used for technical excellence, or just good helpful advice. Not related to trader status at all as I have seen lots of people that post good helpful advice yet have constant complaints about them as traders.
Also like has been mentioned, alot of newbies like myself do buy/sell alot of new stuff. I have spent a fair bit in a few weeks. Dave can vouch for that. Although I am new here pretty much.
Also a point regarding postage, yes we all "should" insure it at full value and have it signed for, yet alot of people don't as it costs them more. It's like speeding I suppose, people do it because you get away with it most of the time. Like postage, most of the timne it's fine cheap ass standard delivery. It's the times it's not that are heard about.
When I sell stuff I always send it by courier, or if small, recorded.
It's not what you know, it's what you can prove in this world. So if anything goes wrong I will help out as best as I can but I will have stated the couriers level of insurance and any shortfall in value if it was nicked I would not compensate for as the buyer would say no to the extra few quid in postage.
This online buying is all about covering your ass, yes there are some real good deals out there, but also some scum that want to scam. Thats why I always use my credit card for buying, unless it's local. Has a record of the deal, and rechargable if the milk turns out to be sour.
Just small things like a few minutes to think "am I covering myself" can go along way. Although it's never 100% safe buying online no matter what.
sorry for the real long reply like, and sure I missed some points I had in my mind like