Is this formal or informal? As in, would he get a professional to do this if he didn't ask you? Furthermore, are you a professional at what you're about to do? Can you give an expert opinion on it?
If you're just friends and you're checking out something, I'd charge $150 dollars total. If you're a professional or expert and he's asking for your services, I'd charge something in between a friend fee and a pro fee. It's really hard to say when we don't know what you're doing or looking at.
-Lasereth