Just type "Magic Supplies" or "Magic Shops" on your google bar and voila!
You can also go to eBay, there's a ton of magic merchants there as well.

If you are in a rural area and limited on funds I'd recommend just getting books that teach the basics on two levels; Slights & Manipulation Methods as well as stage-craft and how to make SIMPLE props. For the latter you might want to get the Paul Osborne books in that they have small and large effects that are relatively easy to make with plans that are superior to most of the older plans that are out there.
Learn the methods and basic concepts and then get resourceful, making your own stuff. This is always the better way to go. But no one can really help you until you know what direction you wish to move into. Playing cards for an example, you can get most anywhere but Fanning Cards or "Manipulation" Cards are a specialty item you'll either have to get the patience to make up on your own (very tedious work) or buy outright... I'd suggest the Nielsen Palming Cards myself but I'm far removed from that world these days, there may be better resources now. But similarly manipulation items like Billiard Balls would also need to be purchased... I'll suggest
http://www.stevensmagic.com/ in that they are the shop I've dealt with most over the years and if they don't have it they can usually find it for you. I've never had an ounce of trouble dealing with them. But similarly, look at the top of each thread here on the forum and you will find resources that are reputable.
