Scoring first word with all 7 letters
You get both.
In fact, there are three bonuses that you can get on your first turn, evaluated in this order:

Double letter score (if you play your word such that it hits one of the double letter scores that are 5 away from the starting square)
Double word score (from the starting square)
Bingo: +50 points for using all your letters

Let's say you play the word &quot;LETTERS&quot;, with the L on a double letter score.  You would get 66 points:

Base 7 for tiles: all these tiles are 1 point
8 points post double letter score (the L is doubled to 2 points)
16 points post double word score
66 points post bonus