I personally do not find expensive wine and liquor worth it. That obviously don't mean all cheap wines are good, but I find the percentage of bad wine I had at $50 - $70 range is pretty much the same as wine around or under $20.
I find the best way is to research online before you buy or go for couple known-good brands. Most of the results actually tend to be on the cheaper side (around $20 for wine, around $35 for liquor).