Bartering, lying and persuasion aren't all noble skills. But hey, you've got to survive somehow, right?
Bartering
1- You pay full price just like everyone else
2- 10- 25% off price
11-19- 50% off
20- 75% off(Free with high enough barter)
Lying and Persuasion
1- Disbelief and any consequences(They won't trust you anymore, or you get arrested or something)
2-8- Disbelief
9-19- Reluctant Belief
20- Belief and Rewards(They trust you more, and may give monies.)