Zero points are deducted in Scrabble for a blank tile at the end. This is because points are deducted at face value, and blank tiles have nothing printed on them.
When used in game play, blank tiles still assume no point value, even though the letter they are used to represent would have had value. One way to use a blank tile in Scrabble is to use it in place of a vowel or low-value consonant, or in place of a hard-to-find letter to complete a high-scoring word. Each set of Scrabble tiles has only two blank tiles, so getting one during game play is rare.