Are you serious? Well, whose paying? Tell your mom you can use eBay for cheaper, but if it's a religious problem, tell your mom that you'll use Toys N Joy's expensive $300 price, and the fact that they even have it and will even give it too you is slim. Heck, they're selling Gatack belts that they don't have (I can only assume) and sell bootleg DVDs. Worse, I heard some kids tried to get some games that said they weren't used, and WERE used, and paid almost quadruple the price. I've heard their customer service is poor, and they say they have Godzilla toys in stock, but don't even. I heard guys who waited half a year for them to get their toys.
Seriously though, point this to your parents. A cheap eBay price vs a $300+ RISK? I'd go with eBay. Besides, if you really think you're gonna get a new toy, I can count those chances slim. I mean, seriously, Boukenger figs that I think are discontinued by now might be used on Toys N Joys. Heck, next thing you find out that you will find a used figure in the mail that was $300+ and you're parents would even be more mad.
If anything, I'd do some eBay or even Yahoo! Auction Japan (for a little cheaper) for a NEW toy, and not some used one. Besides, isn't that the same toy that was made by the Chinese and shipped to Japan's companies so that they can sell to small stores that eventually end up possessing it and selling it to you? Same purpose if you were to go down to Wal-Mart to buy something. If anything, a NEW toy would be "less sinful" (I assume) compared to one who someone else that could have infected/impurified it (seriously, some people do some pretty nasty things to some toys).