EarthWise CST00012 18-Volt 12 Cordless String Trimmer
If you want the best bang for the buck string trimmer on this list, look no further than the Earthwise CST00012 18-Volt 12-Inch Cordless String Trimmer. It’s one of the least expensive units here yet still gives decent power for what you get. The 18 volt battery is a NiCad design, which keeps the cost down over the prevalent Li-Ion batteries on this list. At more than eight pounds it's a bit on the heavy side, but it will give you an approximate 20 minute continuous run time, good for most suburban home trimming jobs.
The handle telescopes to accommodate anyone’s height and the head has a three position adjustment for edging and trimming. About 80 percent of homeowners don't need a cordless bigger than this, and if you want more run time, get another battery. In most cases, doing that would be more cost effective than laying out the big bucks for a top of the line cordless.