I know iam not an expert in this section but I can suggest against ebay. Ebay users usually end up in a sweet scam that you can;t get yourself out of.
I have bought and sold nearly 1000 items on eBay. The trick is to thoroughly check out the seller before you buy. First, look at the feedback. If not virtually 100% positive, forget it. Second, reliable sellers often have a website you can visit where the sellers policies are articulated. Third, never buy anything without a generous money-back return policy. Send the seller a question and ask for his phone number. If he responds, you can call that number and check him out by phone. You should be able to tell if the seller is technically astute and both capable and willing to support what you might buy from him.
I am not certain if eBay's Buyer Protection program (See eBay Buyer Protection Page) is available outside the US. Under this plan, eBay guarantees satisfaction if there is a problem that cannot be resolved between buyer and seller. In addition, on most technology-based items, you can buy an inexpensive warranty from SquareTrade (again I'm not sure if this is available outside the US).
Even if the Buyer Protection Plan and Warranties are not available in your country, if you follow my advice, you should have a positive experience.

