There is no difference between negotiating a $5,000,000 deal or negotiating a $5 knick-knack at a garage sale.
The principles of negotiating apply no matter what the situation is.
The key is knowing how to read people and being able to convince them they need what you are selling.
Reading people and being able to convince people are life skills that you will never regret having. They are skills that can be used on a daily basis so do what you have to to learn them.