I am an on again / off again subscriber to zamplebox. They offer a good value for $25-$30 if you go by the price of the juice individually and you can set up your preferences to some degree so you don't get juices you hate. I love 20% of what I get, dislike 20% of what I get, and the others are usually just pretty good.
It's a great service for vapers in the first year or so because it throws a number of juices and vendors at you so that you can find out what flavor profiles you like and discover new vendors.