Digi-Key is a distributor of electronics components, and we love to buy our bits and bobs from their site. Resistors, regulators, switches, leds, they've pretty much got it all, and tend to have high-quality components at competitive prices.
Visit the Digi-Key site here.
Adafruit is probably the best distributor of open-source computer chips and accessories for DIY electronics projects. They have tutorials and starter kits as well, to help those new to the craft.
Visit the Adafruit site here.
We all know Amazon as the web's premier provider of goods shipped to your door. Many do not realize that Amazon also offers AWS; an infinitely expandable computing, storage, database, and content delivery vitrual server service. AWS even offers a free service tier, which includes offers that expire 12 months following sign up and others that never expire.