I wouldn't say never order from a fake website if you like the look of the product and are happy to accept its fake. Some fakes are better than others, I'd imagine.
But I would say ALWAYS make sure you pay Paypal, because you can "force" your money back by claiming through paypal if it goes wrong, and always check where the website is based, because if its not in the UK but say China, it will cost you money to send the bag back, and you really need to send it back with proof of delivery, not just proof of postage, if you do want to claim through paypal.
So if there is, say, a website based in the UK selling fake Raybans, you don't mind if they are fake as long as they look right, and they take paypal, go for it, because the most you would lose is £5 sending them back special delivery if they turn out to be absolute crap, whereas larger items sent from China could be more ££ and stress than its worth...