Use 'overcharge' to imply that a price is unfairly high, taking advantage of customers. After the concert, the vendors overcharged for simple bottled water.
Pro Tip 2/3
Expressing Complaint
Mention 'overcharge' when complaining about a price that seems too high for the value received. I will complain to management that we were overcharged for our meal.
Pro Tip 3/3
Service Disputes
Use 'overcharge' in situations like disputes or discussions about billing for services. He disputed the invoice, claiming the company had overcharged him.