Yes, TEA is a Scrabble word!

Letter values in Scrabble US: T 1, E 1, A 1.

Is it a valid word?

TEA is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a beverage made by steeping tea leaves in water
a light midafternoon meal of tea and sandwiches or cakes
a tropical evergreen shrub or small tree extensively cultivated in e.g. China and Japan and India; source of tea leaves
a reception or party at which tea is served
dried leaves of the tea shrub; used to make tea

Also: afternoon tea, camellia sinensis, tea leaf.