not too tough to find, it's on the windowsill above the snack mart.
jump from the stairs to the cover on the wall, then across the street onto the outcrop, walk on that outcrop around the corner then use the flowers to get to the end of the street and use that outcrop to reach the window. Hope this helps!
P.S. you can use it on the store clerk, same way you use the cucumbers and carrots from the shop