The best way to learn about wine is to taste wine. But, it's understandable if you would prefer to taste before you commit to buying one. That's why one of the great things wine retail stores offer are regular wine tastings that focus on a region, producer or varietal. For anywhere between $5-$25, you can taste a selection of wines and if you find one (or more that you like) you can buy it on the spot!
In a city like Los Angeles, you can most likely find an in-store tasting on any given night/day of the week. Here is a list of some of the local stores in Los Angeles that offer tastings.