Why $25?
Literary agents aren't supposed to charge to read. Publishers sometimes do, and you deserve to know what you get for it. Here it's this: your pages read by the person who makes the decision, and a written answer in three weeks. Most writers wait months for a form reply, or for nothing.
The $25 doesn't buy a yes. It isn't a deposit or a credit toward anything. And we don't follow up a reading with a sales call.