ASANTS... our store is allowed to flex fast selling product to the check lane endcaps.
I would look at the ad, and try to put up something that is a good deal... usually something from Health and Beauty, Market or Chem.
but, during peak Back To School, something like ziplock baggies, hand sanitizer, clorox wipes ... would be good.
during summer - small beach toys, sidewalk chalk, water balloons, or bubbles...
during Easter - small toys and things to fill Easter Baskets (candy, artificial grass, etc.)
whatever the Hot item is -- like stuff to make slime, or fidget spinners (though those might be fading trends, there will be a new trend/hot item for the holidays)
Focus on the next holiday -- like Labor Day -- Bar B Q items, paper plates, cups, napkins....
or stuff for Back to School lunch boxes -- cases of single serving snacks, fruit cups, fruit snacks, 8 oz bottles of water ---- anything that would be good in a lunch for school -- People may have already purchased their supplies, but they will need to continuously stock their pantry