Absolutely true in South america. I've had a ton of different sub-$5 wines. In my experience, if you randomly buy 20 bottles of $5 wines, one is better than a $100 bottle, plus you also get some 5 great wines, 10 good ones and the rest works for cooking.

The best wine I've ever drank cost less than $3 and was produced in a tropical (21 South), 800m altitude region of Minas Gerais, Brazil. Never assume wine is bad because it's cheap or from somewhere.