[octopus]

I have used eBay only this one time. Perhpas some other people could give better advice.
As far as I know, when you sell something on eBay, the person who buys item from you gives a feedback that anyone can read. So if you sold 20 items and 20 people were happy with you, you get 100% record. I would suggest to buy from people with 99% and above. If they sold small number of items, % number is not tellling you much. Read the feedback from other people.
See if you can find it in stock in shops.