I would recommend Amazon above anything else, because you can frequently find ah-mazing deals (I once got a $110 dildo for $30 just by waiting for a sale!) Be sure to only purchase from high-quality sex toy manufacturers;
Vixen Creations,
Tantus, and
Lelo are the three I would recommend most highly to search for on Amazon - The hyperlinks will take you to the official websites, where you can get an idea of what they offer/what you want to search Amazon for. There are of course lots of $10 jelly toys and things which are absolutely horrible for your body mixed in with all of the good toys, so be sure to research/make sure you're only purchasing 100% safe toys (all of the brands I linked are 100% safe!)
Aside from Amazon, the Tantus
grab bag is a great deal for getting quality toys. You don't get to pick the colors, but get a ridiculous discount for the same high-quality toys.