The Cape Fear Rocket Club heads out to the dunes of Kittyhawk, North Carolina every August to pierce the sky with their fiery projectiles. An enterprising seller of t-shirts has devised a series of designs that capture the spirit of the event in silk-screened splendor. His employees can be found on many of the major intersections hawking his wares out of the backs of station wagons and pickup trucks. What is the best way for this business to ensure that sales data entry is efficient and accurate?