On my drive home, I pass several micro-breweries. For about $10 you can get your growler filled to take home and enjoy. If you don't open it, it is supposed to stay fresh for days. I only buy it when we plan on drinking it right away. It works out to about 4 pints, which is the perfect for two people at the end of the work week.
If you don't have a growler, most breweries sell them (filled!) for you to take home. Then, all you need to do is keep it clean and remember to bring it with you when a brewery is nearby. I've had the growler pictured below for years. This most recent fill-up was at the Maritime Pacific Brewery. Their Flagship Red Ale is smooth and sweet with a mild hoppy finish.