Eleocharis montevidensis, also know as Giant Hair grass, is a terrific background plant that does well form Medium-light to high light.
This plant gets very tall, so it is excellent at hiding those filters and heaters in your aquarium. You can cut the leaves to any size you would like, as cutting the leaves does not hurt the plant.
Light Needs: Medium
Growth Rate: Fast
You are buying one potted plant. The leaves are approx. Fifteen or more inches tall at this time.
Potted plants are better to start with then "bunched" plants as they have their entire root system intact, which makes them less likely to go in to shock when transplanted in your aquarium.
Giant Hair Grass is a bottom feeder so only plant the roots, Not the plant itself (where the green starts) in your substrate. Planting this plant too deep can cause melting or yellowing of the plant. Adding fertilizer tabs a couple of inches from the roots is suggested.