I work at a retail store and when something rings up higher than the price should be we give it to them for the stickered price (or free). If something is stickered for 20 and it rings up 10 then they get it for 10. I don't think they can raise the price if it is the right item no matter what...
WARNING
May Contain spoilers about previous episodes along with substantial information about some of the events that happened last episode.
Warning #2
Information may be mushed together and hard to understand or may have no point at all. Read at risk of intelligence.