I did a logo for a guy I know. Not a friend as such but I used to work with him. I charged him £200, because it was about 5 minutes' work, and I needed the money.
He's come back and asked me for two more logos, exactly the same just with different text - for two different companies. Not sure why he thinks this is a good idea, either way he wants to pay £25 for each of them.
Now. Obviously it's going to be another 5 minute job, so as an hourly rate that's fine and dandy, but I feel like to say yes is to totally devalue the industry.