If you read the fine print, and look at sellers' feedback ratings, you should be fine. Sellers are held accountable to provide items as described in listings. Otherwise, you can have a full refund, especially if you use PayPal.
eBay is an online market with auctions and instant buys. Sellers from all around the world participate. You do need to use judgement when shopping and stay away from risky sellers. Safe for children to view/browse but not safe for children to make purchases as there are scammers out there.
This is a good site, you just have to be smart when you use it. People that marked it under "fraud, scam, phishing" Should have marked it "Bad customer experience." It isn't necessarily Ebay is the one that scams you, its the Users that scam you. Make sure you find a product with a person that has good reputation, and has a policy where you can ship it back, preferably them paying for it.