I agree that with the open source designs that you don’t know what you’re buying unless you go to a trusted distributor. The closed designs are not so easy to stamp out with counterfeit parts though. Two brands of low-cost components (some of which I know are supported by ArduPilot) are Matek and Kakute, and these are available from distributors like getfpv and teamblacksheep.
One example, the Matek F405-Wing, has a large presence on the forums in threads like this one: E-flite Convergence Using Matek F405 Wing