Subscribe to ZampleBox or Craft Vapery--or, any of the other services out there. At Zamplebox I spend $27 and receive about $40-$60 worth of mid-shelf to high-shelf juices. For example, this month I received 3 15ml bottles that were incredible, two 10ml bottles that were just OK and one that''s good but not really my thing. In general, it's worth it if you want to branch out and expand your palette.
Sample packs from Seduce Juice are highly recommended, especially when they run a sale. I'll also second ITC as a good budget vendor.