If looking for a rest on the cheap, most any old sandbag type rest will work fine for general sighting-in and target shooting. The most important thing is that you do everything the same for every shot. Placement of the rifle on the shoulder and front rest, trigger squeeze, cheek weld, breathing, body angle, everything. No different than other types of shooting (standing/offhand, prone, etc). The rifle handling has to be good for accurate shooting...period.