Final answer:
In 'The Purloined Letter', Stider wants a significant and increasing reward for information about a missing letter.
Step-by-step explanation:
In the story 'The Purloined Letter' by Edgar Allan Poe, the character of Stider is offering a reward for information about a missing letter.
While the exact amount of the reward is not stated, it is described as a 'very great deal' and 'a very liberal reward.' The reward is of such significance that Dupin, another character in the story, would be willing to give a check for fifty thousand francs to anyone who could obtain the letter.
The importance of the letter is increasing, and the reward has been recently doubled. However, even if the reward were tripled, Dupin could not do anything more to increase it.