How do I use an expert?

Experts are used to find out the appraisal of an item. Level one allows you to find out the worth of an item, level two allows you to find a qualified buyer at a higher rate. After putting an expert on speed dial, click on an item on your shelf and you will have the option to have it appraised. Each time you use an expert the experience level of the expert will go up - eventually unlocking the next level.