Your rental cost will depend on the size and type of trencher you choose. Ride-on trenchers are more expensive at roughly $312 a day, $780 a week, or $2,056 a month for a 36 inch model. Walk-behind trenchers are considerably less expensive. Plan to spend about $130 a day, $416 a week, or $936 a month for a 24-inch model. A 36-inch walk-behind trencher will cost a bit more: $156 a day, $448 a week, or $1,131 a month.