You are about to finish your project, reaching out for your trusty cordless drill just to find out that the battery is empty, &$*!@!$. We all know this happens just too often. Batteries used in cordless drills are usually of Ni-Cd chemistry which has high self-discharge rate. This means that chemical reaction inside the battery is reducing it's charge without any connection between the electrodes, just by sitting on the shelf. Ni-Cd are especially prone to this losing it's charge pretty quickly. Another problem is that these batteries are usually of low quality with low number of possible charging cycles.
You need a decent charger that can charge all your batteries including LiPo, LiFe, NiMh, NiCd? If you are in RC world in last few years, it would be impossible to miss one brand know for it's large products portfolio and "best bang for the buck" philosophy, Turnigy.
There surely are cheaper alternatives but TGY-306G-HV is good "bang for the buck". Thanks to it's dimensions it's usually used as drop in replacement for cheap Orange servos and it surely is an upgrade in terms of quality.
New Taranis RC transmitter from FrSky is maybe todays best bang for the buck, but why on earth did they design it for obsolete NiMh battery packs. Taranis battery that comes with transmitter is only 800mAh and since it's NiMh with high self-discharge rate. This means you have to charge it every time you are planning to go to the field.