1) DHGate may well be crappy copies of good equipment, but a burning taste is probably either not enough juice getting to the coil, or something like that which could be fixed... You can find a lot of posts about it.
2) You can start by looking at the "Forum Suppliers" page - link way up top. Most of those are vendors people here go to!
3) What do you mean by "Bulk
eliquid"? Are you mixing your own juice, and need a gallon of strong Nicotine base? Or are you looking for a vendor that sells ready-to-vape flavors?
A couple favorite sites of MINE (just add the dotcom):
DiscountVapers (hardware only)
MtBakerVapor (mostly juice, but not bad deals on some equipment too)
MrELiquid (juice mostly)
MyFreedomSmokes
MyVaporStore
SunVapers (Kanger, and Kanger)
My local vapor store is a bit overpriced from what I've seen other places around the state. I've been looking around online for some good stores to purchase from, but have not had any luck so far. I recently ordered some kanger tanks through DHgate, but they ended up being cheaply made and cause a burning taste whenever it heats up too much because of the thin thin thin metal they used to build it. Any info would be appreciated.