You mean Flavorings? You need to use professional concentrated flavorings which are usually in PG base and have absolutely no natural sugars. Sometimes Walmart carries Lorann professional flavorings - however Lorann flavoring are often extremely concentrated and not recommended for beginner DIY.
I recommend Flavourart or Flavorer's Apprentice flavorings. See DIYFlavorShack, OneStopDIYShop. Liberty-Flights.com sells small bottles of Flavourart and accepts Paypal.
Also go to the ECF DIY section and read the guide in the sticky
threads. That includes lists or links to lists of which flavoring flavors that have chemicals that should not be vaped or are in oil (much harder to use) etc.
DIY E-Liquid