This is the 5202nd most frequent Russian word.
низкую
"Low" (feminine singular accusative form).
Here the word 'низкую' describes the noun 'цену' (price), indicating its characteristic as low.
Она выбрала низкую цену на товар.
She chose a low price for the item.
In this example, 'низкую' modifies the noun 'калитку' (gate), pointing out its physical height.
Он заметил низкую калитку у входа в сад.
He noticed a low gate at the entrance to the garden.
Here, 'низкую' refers to the 'степень сложности' (level of difficulty), indicating it is not high.