This may be contoversial but I don't think there's that much correlation between price and quality. It's all just PG/VG + nicotine + artificial flavourings. The 'boutique' places tend to offer more individual flavours they have mixed themselves. The important thing is to find the flavours you like, along with getting a blend of PG/VG that suits you and getting the nicotine strength right.
I vape a lot of Hangsen (£2/10ml, chinese, 80/20 PG/VG), some Joose Juice (£1.49/10ml, made in UK, choice of PG/VG ratio), occasionally Alchemist's Cupboard (UK made, £4.59/10ml, 50/50 PG/VG) and occasional T Juice (UK made, £5.95/10ml, 80/20 PG/VG) - and rather a lot of Grant's Vanilla Custard (UK made, £12/30ml, choice of PG/VG). All the ranges have some flavours I like and some I don't 
The way I started was buying a lot of different sorts of flavours in the cheap brands and working out what kind of flavours I like and which I don't. I think I saved a bit by discovering early on, for eg. that I hate menthols and love vanillas, before shelling out for something that's £6 a pop.
PG/VG ratio -
PG for flavour and throat hit
VG for lots of vapour
Some people are a bit sensitive to PG and do better on a VG based juice.