An Errand for Fuller

Go to Winthrop at Candlekeep Inn and purchase a set of 20 bolts, and take them to the barracks. There you will give your bolts to Fuller who apparantly can't walk up the street to get some himself.

When you talk to Fuller, ask him if he has any errands for you to run. Talk to him again and give him the bolts for your reward, 10 GP and 50 exp.

Some sources say that Fuller will give you a Dagger +1 instead of 10 GP.