Fuck me, if you can't tell the difference between $4 wine and $200 wine, you should just be drinking $4 wine.
Also, if anyone wants good wine cheap, get on the K&L mailing list. They'll often have highly rated wine for $10, 15, 20 bucks - stuff that punches way above its weight.
The real deal is repeatability. Given blind tastes, can you repeatably know which ones you consider good? If so, you can probably do a decent job of ignoring the wine label, finding what you like, finding what you like cheap, and saving yourself quite a few dollars. If not, if your perception is all over the place, then save yourself some money - pay a friend $3 to tell you that your $7 wine actually cost $50, and you've saved 40 bucks!
Though I might point out that considering how subjective taste is, considering how much people value "the experience," an expensive label will literally make wine taste better to many people.
While I'm not much of a wine guy, I can very easily tell the difference between hard alcohols... not that the quality necessarily correlates with price, but I can tell what I like with very high repeatability. (Hell, someone set me up a blind tasting of my own stuff, I got it right, despite not even having tried one of the bottles yet.) The good news there is that, just like wine, you can find good stuff for a low price. The bad news is that I can very easily tell good from bad, and the really cheap crap ($9 bourbon) doesn't make me nearly as happy as $26 bourbon. The good news is that I'd rather have $26 bourbon than $126 bourbon even if they were the same price.