If I understand things correctly, the lawn mower that harbor freight is selling is electric, but instead of needing a cord to follow you around, the mower has a battery pack.

In the U.S. people that live in the cities proably do not need to think much about lawn care, but around where I live a common sized yard is about 1/4 acre (a square area that is about 75 foot long and about 150 foot wide) so a corded electric mower is not the most usefull tool :)