Some hackers may ask themselves this question. You may have seen one of these on the black market for bilge rats and wondered what they were. Maybe you have enough doubloons, but don't want to spend it on an expensive trip. So what exactly is a letter of recommendation for?
A letter of recommendation gives the player an additional level of reputation. No matter how close or far you are to the next level of reputation, this letter will automatically grant you a higher level. The letter is available for 30 doubloons, not a hefty price compared to store trips. You can purchase a letter for each trading company except Reaper's Bones.
Although this is a quick way to level up, you can only purchase one Letter of Recommendation with each content update. These arrive monthly, so you can view them as one letter per company, per month. After that, you'll need to earn your Rep the old-fashioned way, by looting and looting.