Amazon has the Worx Landroid M WR147 20V Robotic Lawn Mower (1/4 Acre / 10,890 Sq. Ft) on sale for $720 with free shipping. Other models on sale include: the WR165 1/8 Acre model for $589 and the 1/2 Acre WR155 model for $895.

• Includes battery and charger. Handles slopes in your yard up to 20°.