I tell folks this all the time (generally those new to the hobby) buy a system/plane/accessories that are common and repairable.  Normally Specktrum, Futaba, HiTec....Also as to planes the ones that come RTF more times than not from some website don't have buddy capability or spare parts so buy at your own risk.  I normally recommend E-Flite, Great Planes, Hangar 9, the big guys who are hobby grade.

Helis are worse.  I like the gents who pay $100 (slight exaggeration) for a 450  heli yet complain when it doesn't perform or when they crash and can't get parts.  You might as well throw it in the trash...Again stick with the hobby grade stuff.....and dealers...Is paying half the price still a deal when you have a crash - which you will - and you can't repair it?</p>