I liked a viognier recently and then noticed the same winery sells a viognier for twice the price. Is it likely to be twice as good?
No. There's even a chance you'll like it less than the more affordable one. (Believe me, I've been to this rodeo many, many times before.)
Wine prices are not exactly based on a scientifically measurable hedonism scale. The situation is not analogous to, say, buying a Samsung 4K television versus a less-expensive Samsung 1080P (forgive the geek tech jargon). With a flashy new 4K you're getting what's known as "ultra-high-definition" versus the 1080P's mere "high definition," a technology that's been the standard for a few years. In other words, you get many more pixels with 4K, and more pixels result in clearly better picture detail. In this case, there is a measurable and objectively conspicuous quality difference. That comb-over on Donald Trump's head? You'll see it more clearly on a 4K set.
Wine, alas, is not made of silicon (though there is silicon dioxide in the bottle glass). Many factors go into pricing. Not all such factors strictly relate to perceptible quality. For example, scarcity can play a big role. Many upper-tier wines are made in small batches from prized single vineyards that (theoretically) yield better fruit. Whether or not the wine tastes better to you or to me rarely matters; it's generally going to be priced higher simply because of supply-demand economics.
Production methods also frequently figure into the mix, and they don't always mean "better" wine, just different wine. Take Chianti as an example. A bottle from Tuscany labelled Chianti Classico will in virtually all cases be priced lower than the same winery's Chianti Classico "Riserva." The latter denotes a reserve wine, generally made from select, exceptionally ripe grapes that are held back from regular production for special treatment. These more concentrated wines typically are left to mature for much longer in expensive oak barrels, where they acquire stronger vanilla-like and spice flavours as well as firmer and more astringent tannins (to render them more cellar-worthy). Oak barrels represent a huge investment for most wineries. But is a riserva always "better" than a winery's normale Chianti? You decide. I know at least one avid, long-term Chianti collector who tends to prefer the regular style of Chianti Classico to the fatter "riserva" style. I also know people who prefer a simple vanilla ice-cream cone to a banana split.