I agree with previous posters. I bought a gimmicked deck via eBay once, and it was defective, so I had to return it. It was an enormous hassle, especially when the seller claimed that I hadn't mailed it back, even though I had photographic evidence of postage receipts. I'd bought one of the cheapest I could find (it was still a $10 item or so, which for my country was quite good), but it was more hassle than it was worth in the end. I later bought a slightly more expensive one from a different seller and that was fine.
You can certainly buy on eBay, but just check the seller. See what their feedback rating is, and try to figure out if they are a reputable magic company. If they are, you should be okay.