I paid $25 for a liter of TH, the least I have ever paid, and it is some of the nicest nick I have used. A whole lot of people think expensive=better. Well, sometimes yes and sometimes no. It just seems to make some people feel better to pay more, whether they are getting better quality or not.
It also comes down to a matter of personal taste. I purchased mainly MFS and wanted to hedge my bets so to speak with long term storage so I also tried NN and VT Premium, IMHO much cleaner nics, and for my taste VT premium is miles above the other two, but... I do not like a lot of throat hit (I use high PG so I get plenty of that without nic hit) or a peppery taste because I use just a hint of flavoring and just do not find that taste appealing with fruit/candy/dessert flavors. I will say though the only nic I had go "bad" on me was cheap nic and by bad I mean nasty smelling muddy dark brown yuck after a few years in the freezer.