itsMilo :
If I go used I'll check to make sure the condition is perfect working condition, and then Ebay will cover me after that.
Ok, having been down this exact road many times before, I have to stop you right there. You need to go carefully read the ebay terms of service. They DO NOT guarantee any product will work or guarantee any product's "Fitness for purpose and merchantability." The ONLY things they guarantee is that the product WILL be delivered to you and that the product will be the same as what was represented in the sellers advertisement. If you take it out of the box and it doesn't work or instantly shorts your system out, too bad, that's not their problem. I've had many in depth engagements with the Ebay TOS and can state this as a matter of fact.
And when the item is used, they're even worse about it. They'll quite simply tell you "it was used, what did you expect". Of course that doesn't mean you can't ever find a good bargain on working but used hardware, just don't expect to cry to anybody including Ebay about it if there is an issue.