Hi Sarajane,
I'm going out on a limb here and probably risk negative reps, but here are my thougths.
From what I gather, she said the item was new, but it was actually second hand, not good on her behalf, you might have a leg to stand on here. YOU, however, assumed that the nail trainer included all the goodies that you were after, but you never actually checked with her. Did she at any point say that these things were included ? If she did, then yes, she conned you, but if she didn't, then it seems she sold you exactly what she was advertising.
Ebay is full of notices everywhere that you need to double check that what you think you are buying is what you are actually buying.
Yes, Ebay has become overun with "businesses" selling there stuff and I suppose the "original" purpose has been lost, but there are still a lot of honest people on Ebay. There are also not so honest people, so that's why YOU need to keep your wits about you.
You were prepared to pay a £100 for something that was being sold on Ebay, you pressed the button. Nobody made you do it. People bid as much as they are prepared to pay for an item on Ebay, now what I think an item is worth and how much I'm prepared to pay for it, is completely different to what somebody else might think.
If you use the example of nail products / manicure tables etc being sold on Ebay, us in the know or who have done our research, think god, that person is being ripped off. BUT as long as THEY feel they are not being ripped off, then it's OK. Yes, in an ideal world the seller would say "Look people, you are paying way over the odds for this", but unfortunately this doesn't happen.
So in your case, I don't think you were "ripped off" (assuming I've got all the facts straight), but that you assumed you were getting something that you didn't actually bother checking the facts for, she sent you exactly what she was advertising (except for the new bit) and now you are unhappy.
I'm sorry if this post offends anyone, but we all know how Ebay works, we all know that there are good guys and bad guys on there. We are all adults and that common sense needs to kick in when we use Ebay. I've personally had some really good transactions on Ebay, with no hickups, simply because I did my homework.
Just my thoughts.
River