[capableweb]

Also, if in your conversation with the person you find out that they actually need a paint brush instead of a pen, don't try to sell them the pen! If you try to sell them something they don't need, you either piss them off by looking like you don't understand them, or you piss them off once they bought the pen from you and realize it won't work for them.

Instead say that probably you don't have (currently at least) what they are looking for, and if they need help in the future to contact you again.