It depends, for me. If I finagle a way to get a substantial discount, I'll happily jump ship and purchase a toy from a less than reputable source. I've bought vibrators from ebay, in the past -- although in that case, they had more than 5 of that single toy in stock, and it was a sterilizable toy.
The first few minutes I'm on a site, I search it for price. After they prove they're not trying to cornhole me, I search for something that proves reputation. An open user format helps -- someplace where consumers are able to freely comment, such as Eden's review system. Or a link to a BBB type profile. I'll often google a business name before I purchase from them, juuust in case it's too good to be true. A surprising number of 'shady' places aren't shady at all... they're just mom&pop style stores that don't know jack about web design/presence.
In any case, I do tend to buy from just Eden. Eden provides me with above average shipping, and average or better prices, a good 8/10. I like feeding the Eden economy, too, because I know if it stays healthy, and continues to make money, they'll continue to provide me with the shipping I adore, at the prices I can live with.
(I sound like I think I can possibly win another contest with this post. :x)