Mouser Electronics has created a mobile web edition to their online store. This is a handy tool for searching, cross referencing and ordering parts. Mouser has a large stock and they ship quickly. Time once was that you could run down to the local electronics store and get just about anything you needed. Even Radio Shack carried a fair amount of small parts, tools, connectors and so on. Since then, the local electronics shop has closed and Radio Shack inventory gets smaller every year. Using a large parts supply company like Mouser or Allied is necessary if any type of trouble shooting and repair is undertaken.
I like the Mouser Mobile site because there is no app to download and install. One simply points the web browser on any mobile device to mouser.com and it will automatically redirect to the mobile site. If that does not work, then m.mouser.com will. The mobile website is easy to browse around, and if needed, a quick call can be made by hitting the little phone icon. Here is more in a video: