Taste is a very personal thing. A juice that tastes good to you might taste like s..t to your friend.
I live in the US and will not buy juice from China cause of the stories about ingredients.
The cheapest juice is what you make yourself. It can also be, sometimes, the best tasting for you since you control what it tastes like.
Juice is Propylene glycol, vegetable glycerin, maybe nic, and some chemicals that fool your tastebuds. The glycol and glycerine are available in several grades and most, almost all, US manufacturers use high quality. The nic is also usually a pharmaceutical grade. The chemicals come from huge companies who sell to other companies who sell to other companies that the juice chef selects and combines to get the flavor he is looking for.
None of this stuff is tested, except by us, for lung inhalation. All of it is tested as a food additive.
One of the determining factors for a juice is the person who comes up with the formula. Some juices will have 10 or more flavor ingredients. It takes a good palette, better than mine, to taste differences and experience to know what to try to bring the subtle flavors out. A hint of something you might not imagine will be the subtle flavor hiding in the background of your favorite juice.
Since taste varies so much look for a reviewer you agree with. Just cause a lot of people like a juice is no reason you will like it but a reviewer who always likes the same thing you do can be a trustworthy guide.
Some juice lines have a personality. I like the juice from Liberty Vapor but they do not have a lime I like so I get that from Allusion. When I want a tart citrus flavor I go to allusion and when I wnat most other flavors I go to Liberty.
Liberty makes a Trix flavor that is dead on but I add a little lemon that makes it better. There is no way I could make a juice with the layers and subtlety of theirs but I like a hint of lemon so I but the juice and add a hint of my lemon.
Making your own juice is like cooking. With a little care you can mix the ingredients from a recipe and have it come out OK. With training and God given talent you can decide that the recipe needs a touch of allspice.