10-50???? Not seen any under 10, maybe on Fasttech or another really cheap site....avoid!!! (the mod not the site) and you can pay $100 or much more for a mech mod. The more you pay the better it should be built and the materials should be better, BUT it doesn't always work that way. Find something you like the look of and then check reviews for it, there are too many around to say which ones are good.
sorry but this is all wrong.
I have ordered 7 mech mods from fasttech and all of them are perfect, never had an issue with any of those, the best one I have is a brass gp paps that was $13 dollars and the switch is miles better than the authentics (not paps) that I've tried.
of course you can find bad clones as well as bad originals but a mechanical mod is a simple tube with some threading on it, I think that the chinese can handle that difficult task.
fasttech sells a huge volume at little margin that's their business model, and a lot of local or online vendors buy at fasttech and sell for 4 times the price here so that accounts for the price diference.
even if the vendors buy directly from the supplier they get say 20 mods, but fasttech gets 200 so their price is much better.
remember fasttech is the biggest store in the world regarding vaping (it's our walmart) so they have bad clones as well as top notch ones, just make your research
now regarding authentic the price is much much more as they make much smaller runs and hire a shop (usually local) to manufacture them, so their price isn't really competitive with the huge factories in china making 100 mods an hour