Plastic shopping bags are a world-wide blight. Millions are used daily. The best thing that can happen to them is that they end up in land fill, which is bad enough. Worse, a huge proportion of them end up as eyesores along roadways. Many of them end up choking wildlife to death.
The compact fluorescent lamp (CFL) is a direct replacement for the standard incandescent light bulb. Although they cost more they use much less electricity. They pay for their higher initial cost by reducing the electricity bill. After about 500 hours of use, they higher cost will be paid off. In a way they are free, since after another 50 hours they will have paid off their entire cost.