You can find parts and directions from RC Builder. There are many models to choose from as well as assembly guides. http://www.rcbuilder.com/Merchant2/merchant.mvc?Screen=SFNT&Store_Code=RCB
You can find parts for your radio controlled truck in hobby shops. You can buy batteries for your radio controlled truck in grocery stores, electronic stores, etc.
If you go to ebay and search for the particular part, i'm sure you could find it. If not, you could try contacting the manufacturer to see what they suggest.
Parts for radio controlled trucks are most easily found in hobby shops or specialty shops that provide parts just for radio controlled items. Other places you can search are auction websites or hobby websites. Try a search engine query to find parts, or try one of the following online hobby shop suppliers: www.rcplanet.com, www.towerhobbies.com, www.traxxas.com, or www.rcmart.com.
Hobby stores such as Hobby-Lobby.com and Towerhobbies.com have a variety of electric radio controlled airplanes to choose from. Prices for electric radio controlled airplanes range from $80 to $350.
There are a couple of websites that sell small boats that are radio controlled in a way a child could use. You can check out the website, Radio Controlled Toys, to purchase.
You might could try radio shack. Another place might craigslist. Keep checking around for your robot parts.I'm sure you'll find it eventually Good luck!
Parts for an antique radio can be purchased at such places as Ebay and Old Radio Parts. Other places where they can be purchased would be Golden Antique Radio Services and Phil's Old Radios.
It depends on your definition of cheap. There are many radio controlled aircrafts that are under $100. You can now find some that are half of that. You can shop for cheaper aircrafts at http://www.redrockethobbies.com/
RC Universe is a website dedicated to all things that are radio controlled. For example, one can find forums, photos, and sales of radio controlled cars, airplanes, and more.
A radio controlled sailboat is a boat that you can take sailing out on a lake or a pond and control it's direction. Here is a site where you can find out more about it and also see pictures: www.hobby-lobby.com
You can find information on this in your local electronic store, you can also go onto radioshack and find information there, as they manufacture most of their radio control devices.
You can find spare parts for Radio Flyer wagons on the Radio Flyer website