KILLSWITCH competitors are encouraged to build their robots using primarily scavenged parts. Thrift stores, yard sales, and local Craigslist ads are great sources for R/C vehicles and toys full of useful hardware for pennies on the dollar. Still, it's likely that all of us will need to order something, and this list of vendors is intended to make this easier.
There aren't very many places we can go to get robot parts in town, and if we don't support them, there will eventually be none at all. Just be aware that everything is cheaper online -- often very much cheaper -- so if there's something you want but can't bring yourself to buy, check internet sources before giving up entirely.
HobbyTown USA - https://www.hobbytown.com
The only source for R/C parts in town. High prices.
Shields Electronics - http://shieldselectronics.com/
The only source for electronic components in town. Talk to Don Hall and identify yourself as a Knox Maker.
These vendors can generally ship the fastest, which can be a real lifesaver if you've waited too long to order.
Jameco Electronics - http://www.jameco.com
Lots of components, modules, and kits. Check out their "Robot Store" particularly. Good prices.
Pololu - https://www.pololu.com/
Good selection of robotics parts and electronics.
Solarbotics - https://solarbotics.com/
Canadian shop with some good motors, pulleys, and the like.
Robot Shop - http://www.robotshop.com/
Canadian source for all manner of robotics and quadcopter-related parts and kits.
Servo City - https://www.servocity.com
Nice selection of servos, motors, and associated electronics.
The Robot Marketplace - http://www.robotmarketplace.com/
Robot and R/C parts, some oriented toward combat robots. Not cheap.
Banebots - http://banebots.com
Motors, gearboxes, hubs, and wheels for combat robots.
Trossen Robotics - http://www.trossenrobotics.com/
Robotics and microcontroller parts and kits.
FingerTech Robotics - http://www.fingertechrobotics.com
Motors, servos, electronics, and hardware.
Robot Power - http://www.robotpower.com
R/C and Arduino-compatible motor controllers
Dimension Engineering - https://www.dimensionengineering.com
Motor controllers and related electronics.
Tower Hobbies - http://www.towerhobbies.com/
Lots of R/C oriented parts - motors, controllers, transmitters, etc. Employee owned.
McMaster-Carr - https://www.mcmaster.com/
Overwhelming selection of all things mechanical, from bearings and fasteners to sheet metal and pulleys.
Adafruit - https://www.adafruit.com/
Maker-centric source for electronics parts, modules, and kits. Kinda spendy. Knox Makers arranges group buys for discounts from time to time.
SparkFun - https://www.sparkfun.com/
Very like Adafruit, but with slightly better prices.
DigiKey - https://www.digikey.com/
Incredibly vast selection of electronic and electromechanical parts.
Mouser Electronics - http://www.mouser.com/
Very like DigiKey, but with a slightly less good search.
These meta-vendors encompass both domestic and overseas sources, so quality and delivery times can vary widely.
Amazon Smile - https://smile.amazon.com/
You can get anything on Amazon, often for cheap. If you buy from Amazon, please use Amazon Smile and choose Knox Makers as your charity!
eBay - http://www.ebay.com/
Everything is available here, too. Deals abound.
These vendors offer particularly good pricing, but are often slow to deliver. Plan ahead and order early if you plan to use them.
HobbyKing - https://hobbyking.com/
Amazing selection of R/C vehicles, kits, and parts. Good prices. Products spread among various warehouses; shipping time variable as a result.
SeeedStudio - https://www.seeedstudio.com/
Maker-centric source for open hardware, electronics, and robotics parts.
RobotDigg - http://www.robotdigg.com/
Good selection of parts for 3D printers, CNC machines, and robotics. Good prices, good quality, medium-slow delivery. Shipping can be costly.
DFRobot - https://www.dfrobot.com/
Maker-centric source for open hardware, microcontrollers, and robotics parts.
AliExpress - https://www.aliexpress.com/
All kinds of consumer electronics and parts, much direct from the manufacturer. Prices are often as low as they get. The language barrier can be challenging.
DealExtreme - http://www.dx.com/
An incredibly wide variety of consumer electronics, toys, and parts. Great prices, decent quality, glacial delivery.
Banggood - http://www.banggood.com/
Similar to DealExtreme.
Knox Makers doesn't endorse any of these vendors. We benefit only through Amazon Smile.