When choosing a power tool consider how robust and powerful you need it to be. This will depend on if you will use the tool often in heavy duty situations or if you only need one for occasional use around the home.
The higher the battery voltage, the more powerful the tool will tend to be. Also, paying more for top brands like DeWalt and Makita will get you a higher quality, more robust tool.
Here is a selection of cordless power tools that will fall under the hammer very soon, so if you want to get your hands on one of these under-priced items, better be quick ...