Ok, so I'll give you this thought to ponder on.
Clero's and cartos are widely available, and not going to say "Don't go to your local vape shop" but....
Wire from TE Temco is around 5-12 bucks per 100ft, if you factor in that most people wrapping a standard coil (Not twisted or spiraled or whatever else can be done) only use maybe 1.1 ft or so that spool should last you a long while.
Quality of materials is something you control with RTA and RDA's, that being said the individual components have to be of higher quality then disposables by the nature of it to last the test of time.
Coils rarely go bad (yes I said it), that nasty funky taste you get is because the wicking material is fouled. In an RTA and RDA typically its easy to change it out, dry burn your coils (heat til red hot for no more then 2 seconds), rewick and your good to go until next time. I get an average of 2-3 months out of my coil builds usually before having to replace.
Wicking material is cheap, really cheap depending on if you use Rayon or Cotton. Also given its size worse case is you keep some in your wallet in a small plastic baggie for those emergency times, carrying around an emergency vape repair kit isn't cumbersome and usually won't take up that much space (I keep mine in my car for instance and its housed in a sun-glass case).
Hopefully this helps out some, I'd say hit up your local vape shop and ask questions of the people rebuilding. If your lucky someone may have and old RDA or RTA they will part with on the cheap.