Stores and companies that deal directly with the hobby of electric planes could help you find an electric rc plane. Also, if you look on Ebay, Amazon, or Craigs List you might be able to find someone who would like to sell one to you.
You can purchase an electric RC plane online from retailers such as Amazon. Once on the page, type "Electric RC plane" into the search field at the top of the page and press enter to bring up the planes.
you can buy them in hobby shops
If it is an electric RC plane then all you will need to pay for is the plane and if you plan on crashing a lot some spare propellers if it is an RTF or ready to fly version. If it is an ARF or almost ready to fly you will have to buy a motor too.
Electric planes can have many uses to them ranging from just recreationally flying them to races, as well as reenactments of wars. http://www.xenonproject.com/rc-airplanes/electric-planes/
In your dreams
The best place to buy RC planes is nitroplanes.com, they have great sales around the holidays!
Yes there is a specific fuel needed to fly a RC Plane. This fuel is: Rapicon Max Power RC Airplane Fuel 15% You can buy it here: www.amainhobbies.com
The price range for an electric remote control plane would vary based on the type of plane you want. A basic one would cost much less than one with more expensive material or a large one.
Both RC plane are awsome because they are both planes.
Personally, I would check out Amazon.com if you would like to buy a RC Electric Boat. This place also offers you some, though. www.offshoreelectrics.com/
Yes, they always have at least 7 different motor speeds never less
There are several places to buy discount RC plane parts. On www.rchobbyexplosion.com for example, you can buy a Megatech Mega Nitor 2 Deluxe Glow Plug Starter for $24.95 which saves you $15. Another good place is www.ebay.com where you can bid on items, potentially saving quite a bit of money.