that depends on what your trying to make
If youre looking for hobby grade, hobbyking.com but if you're looking for toy grade, then I dont think you can.
One can buy a Nitro RC Buggy at many different toy and hobby stores including RC Hobby Models and The Entertainer. They can also be found online at Nitrotek, eBay and Amazon.
Lego, Tyco, New Bright, Nikko
AirWolf Rc can be purchased from multiple online retailers for instance walmart.com, amazon.com and practically any store that has a hobby or toy department.
I always find that there are many nice little RC Helicopters at online RC shops, but they can be found at anywhere from eBay, to your local toy shop. Many places that I have found useful are eBay and other shopping websites, online RC suppliers, toy shops, electrical equipment shops and hobby stores.
manager of grave rc hobby shop
RC toys are helicopters and planes flown by a remote control (R.C). You can usually get these at special hobby shops and online (I.E Ebay.) Even Toys R Us.
An RC Submarine is a submarine purchased at a toy or hobby store that is run by remote control. If you want to see a sample of an RC Submarine you can find one here: http://www.amazon.com/Swimline-RC-Submarine-27-MHz/dp/B0037M4Q3A
For a good hobby grade truck look to spend about 150 and up for electric and 300 and up for nitro
You can look in hobby or specialty stores to find various types of RC Hummer toys. You can also fing them in places like toysrus.com which can ship the toy right to you.
You could buy a gas powered RC boat from any hobby stores or even a toy store. Or WalMart, Kmart or even Target. You could get a gas powered RC boat from Radio Shack too.
Some models of a sedan car may be found at a hobby store. Some examples of hobby stores are Hobby Town, Hobby King, Horizon Hobby, RC Buyers Warehouse and RC Boca.