I will do my best not to come off like some wine snob ass hole in this post. Anyone that tells you there is no difference between a good $15 bottle and a good $50 bottle, even to an unrefined palate is lying. That isn't to say there aren't good bottles of wine under $20, there are many. There are also many bottles over $50 that aren't very good.
Thing to remember with wine is that it is all personal preference, whatever varietal, vintage and producer you like is all up to you. That is why it is tough to give advice on wine, what I like may not be what you like. Personally, I would only cook with most of the wine they sell at Trader Joe's. They have made a conscious decision to sell low priced wine and there probably is some decent stuff there.
I think BevMo (
www.bevmo.com) has a better selection and equally good prices. They also have a large selection of affordable wines and great deals on wines. One of their sales is buy one bottle and get the second for a penny. Not everything in the store, but typically a lot of their $20 and under bottles. They are all over California. I buy most of my stuff there, from K&L (
www.klwines.com) and Wine Club (
www.thewineclub.com). K&L is located in Redwood City and just opened a store in LA, Wine Club is in SF, San Jose and Santa Ana. Both stores have great prices and amazing selection.
Under $20 bottles that I like
Kim Crawford Sauvignon Blanc ~$12 at Costco
Villa Maria Sauvignon Blanc - I think it is under $10
Lawson's Dry Hills Sauv - ~$12
Rosenblum Vintner's Cuvee Zinfandel ~$8-9
Falesco Vitiano Umbria ~$9
Coppola Claret ~$14
Mark West Pinot Noir - they have one that is like $10, most of their Pinots are good.
E Guigal Cote du Rhone ~$10-12
Franciscan Oakville Cab ~$20
I don't tend to buy and drink my wine right away, I typically lay it down for a while, depending on the quality and type of wine. The tannins tend to mellow over time, so consider laying it down for a year or two before drinking. You may find that you like the wine better. If you are serious, you should keep tasting notes to compare what you thought say two years ago against the same bottle. It will give you an idea how long you may want to lay down future vintages of the same wine. You should also store your wine properly, fluctuating temperatures ruins wine and warmer than ideal temperatures (53-58 being ideal) will age wine quicker. Plus, once you start drinking wine at appropriate temps (53-58 for red and, depending on the varietal of white, colder), you won't want to drink it at the room temp that most people serve reds.