Homebrew ant killer made from sugar, borax, and water is very effective in keeping ants out of the house. Dissolve a half cup of sugar with 1.5 tablespoons of borax into 1.5 cups of warm water. Then dip a cotton ball into the solution and set it on a countertop (where kids and pets won’t eat it). The ants will flock to it and 12 hour later, you won’t see any more ants for a long time. Get a one-pound bag of borax on Amazon for $8.50 (which you can also use to make slime).
Image: Balaram Mahalder/Wikipedia