They've had good wines. They like bad ones.
Just wanted to point out that even many wine connoisseurs agree that inexpensive wine does not equal "bad" wine. 
I'm aware! But their favorite wine tastes like Shasta or Nehi or some other fruit-flavored soda. I'm not being condescending here. Some people like, say, a nice peppery shiraz. Other people like grape-flavored red wine with a slight, inexplicable fizz. Buying them, even, my favorite ten buck bottle would, my SO says, inevitably be greeted with "but it's so sour" or whatever. I'm not trying to be a wine snob. But I am trying to get them something they'll actually enjoy.