It depends what you are looking for Josh, if you want to mix everything from scratch you have good products from all the flavour houses and each will have their own traits that need experimenting If you just want to mix on a budget you have loads of one shot flavours already available that are pre-mixed, you just then make them into eliquid. Dripworx, South Coast and BLND are worth mentioning. For BLND you could try our site, Mixshop or Chefs Flavours - infact on Mixshop and Chefs there are a few different ranges available so pick and choose what suits.
It's a learning curve, you will find some flavours just don't mix well r may not suit you. That's why many people prefer pre-made eliquid as the work has been done to get them saleable, however lots do enjoy learning the nuances of flavours to be able to mix their own. It's swings and roundabouts.