Lets put together a list of our favorite vendors...
I'm very new to DIY, as in, I just mixed my first batch yesterday. I think having a nice aggregated list of suppliers would be great for newbs (like myself).
Another Wizard Labs nic fan here, but I also like to get my flavors and bottles from Ecig Express, they stock a wide variety of flavor manufacturers and have a lot of good DIY gear in one place so you can minimize shipping.
So far, I've gotten most of my flavors from The Perfumer's Apprentice. Great selection and the reviews often give a good starting point to what percentage to use of a particular flavor. I still get my VG from WalMart for convenience sake, and I've barely used any of the gallon of PG I bought at Tractor Supply Co. As for nic, I'm still using up what I have from a sale at GourmetVapor, but intend to buy from WizardLabs from now on.
What department in Wal-Mart would I find the VG ?
I found it near the pharmacy/beauty supplies section. Often near the Hydrogen Peroxide and Isopropyl Alcohol. Hope that helps. It's a little 4 ounce clear bottle with a white label that says Glycerin. Should be around $3, I think. I've heard some people think this VG is not very good, but I've had no problems with it. Just FYI.
Flavour Art (situated in Italy but I'm sure they'll ship outside the EU as well) has a lot of great flavors and they're really making an effort to make sure they're safe for vaping. They clearly mark all flavors that have diketones and they even do toxicological studies.